Document Lafayette_doc_1d9df48354

Standards and Specifications Section 100 Title, Scope and General Conditions Page 1 Section 100 Title, Scope, and General Conditions 100. TITLE, SCOPE AND GENERAL CONDITIONS 3 101. TITLE 3 101.1. 3 101.2. 3 101.3. 5 102. SCOPE 6 102.1. ALTERNATE MATERIALS AND METHODS OF 7 102.2. MODIFICATIONS 7 102.3. TESTS 7 102.4. ORGANIZATION, ENFORCEMENT AND 7 102.5. 8 102.6. VIOLATIONS 8 102.7. NO WAIVER OF LEGAL RIGHTS 8 102.8. CONTRACTOR’S LICENSE AND 8 102.9. WORK 8 102.9.1. Working 8 102.9.2. Emergency 9 102.9.3. Final Cleanup 9 102.10. CONTROL OF WORK 9 102.10.1. Authority of 9 102.10.2. Authority and Duties of Inspector 102.10.3. Contractor’s Responsibility for Work 102.10.4. Removal of Unauthorized and Unacceptable Work 102.11. CONTROL OF MATERIALS 102.11.1. Storage of Materials 102.11.2. Defective Materials 103. GENERAL CONSTRUCTION CONDITIONS 103.1. PROTECTION OF PUBLIC AND UTILITY INTERESTS 103.1.1. Public Convenience and Safety 103.1.2. Protection and Restoration of Property and Survey Monuments 103.1.3. Surveys 103.1.4. Survey Monuments 103.1.5. Use of Explosives 103.1.6. Protection of Streams, Lakes and Reservoirs 103.1.7. Dustproofing 103.1.8. Traffic Control, Barricades and Warning Signs 103.2. USE OF CITY WATER 103.3. PAVEMENT CUTS 103.3.1. Pavement Replacement Construction Requirements 103.4. PUBLIC UTILITY MAINS 104. INSPECTIONS 104.1. ADDITIONAL INSPECTIONS AND REINSPECTION 105. PLANS AND SPECIFICATIONS 105.1. CONSTRUCTION PLAN REQUIREMENTS 105.1.1. General Requirements 105.1.2. Plan Details ---PAGE BREAK--- Standards and Specifications Section 100 Title, Scope and General Conditions Page 2 105.1.3. Profile Details 105.1.4. Water Supply Construction Details 105.1.5. Wastewater Construction Details 105.1.6. Grading and Drainage Plan 105.1.7. Street Construction Details 105.1.8. Erosion Control Plan Details 105.1.9. Easement Widths 105.1.10. Specifications and Documentation 105.2. ENGINEERING REPORTS 105.2.1. Preliminary Reports 105.2.2. Preliminary Utility Report Requirements 105.2.3. Preliminary Geotechnical Report Requirements 105.2.4. Preliminary Traffic Analysis Report 105.2.5. Preliminary Drainage Report 105.2.6. Final Engineering Reports 105.2.7. Final Utility Report 105.2.8. Final Traffic Analysis Report 105.2.9. Final Geotechnical Report 105.3. FINAL DRAINAGE REPORT 106. ACCEPTANCE PROCEDURES 106.1. GENERAL CONDITIONS 106.2. CONSTRUCTION ACCEPTANCE PROCEDURES FOR SUBDIVISION PUBLIC IMPROVEMENTS 106.2.1. Final Inspection 106.2.2. As-Built Drawings 106.2.3. Repairs and Replacement 106.2.4. Warranty Inspection 106.3. ACCEPTANCE PROCEDURES FOR PUBLIC IMPROVEMENTS CONTRACTED BY THE CITY 106.3.1. Repairs and Replacement ---PAGE BREAK--- Standards and Specifications Section 100 Title, Scope and General Conditions Page 3 Section 100 Title, Scope, and General Conditions 100. Title, Scope and General Conditions 101. Title These regulations shall be known as the City of Lafayette Standards and Specifications for the Design and Construction of Public Infrastructure, 2004 Edition, and may be cited as such and will be referred to herein as the Standards and Specifications. 101.1. Purpose The purpose of these Standards and Specifications is to provide guidelines, acceptable standards of design, construction, quality of materials, use, location, and maintenance of all public improvements and common facilities including, but not limited to, water reclamation systems, water supply systems, storm drainage systems, streets and appurtenances thereto. 101.2. Definitions Whenever the following terms are used in these Standards and Specifications, they will be defined as follows: Bonds - performance, labor or material payment bonds, irrevocable letters of credit and other instruments of security furnished by the developer or contractor and his surety in accordance with the Subdivision Agreements or other Agreements with the City. City - the City of Lafayette acting through the City Council, the City Manager, or an authorized designee, except in Section 800 where City may be defined as the City of Lafayette acting through the Director of Parks and Recreation or an authorized designee. City Code - the latest, officially adopted Lafayette Municipal Code. City Engineer - the City Engineer or authorized designee. Common Facilities - facilities serving or held in common title by the owners or occupants of two or more dwelling units or commercial or industrial enterprises and covered by these Standards and Specifications. Contractor - a person that undertakes to construct, alter, move, demolish, repair, replace, excavate or add to any public improvements or common facilities covered by these Standards and Specifications. Days - calendar days unless otherwise specified. ---PAGE BREAK--- Standards and Specifications Section 100 Title, Scope and General Conditions Page 4 Developer - the person or persons legally responsible to the City for construction of improvements within a subdivision. Director of Public Works - The City's Director of Public Works or authorized designee. Equipment - all machinery and equipment, together with the necessary supplies for upkeep and maintenance, and tools and apparatus necessary for the proper construction and acceptable completion of the work. gpcd - gallons per capita per day gpm - gallons per minute GRC - galvanized rigid conduit. Inspector - the authorized representative of the City Engineer assigned to make detailed inspections of construction work to assure compliance with these Standards and Specifications and the plans as approved by the City. MGD - million gallons per day. Plans - profiles, cross sections, and drawings and supplemental drawings approved by the City which show the locations, character, dimensions or details of the work. psi - pounds per square inch. Public improvements - improvements under the ownership or control of the City including but not limited to the components of the water system, wastewater system, street system, park system and storm drainage system covered by these Standards and Specifications. The term also includes similar improvements being built in connection with a subdivision which are intended to be dedicated to the City. PVC (Polyvinyl Chloride) - a strong, tough plastic based on resins made by the polymerization of vinyl chloride or copolymerization of vinyl chloride with minor amounts (not over 50%) of other unsaturated compounds, which are fashioned into sheets, tubing, pipe, conduit, containers, insulation, etc. Special provisions - special directions, provisions or requirements peculiar to the project and not otherwise detailed or set forth in the specification. Standards and Specifications - the body of directions, provisions and requirements contained herein, describing the method or manner of construction and the qualities and quantities of the materials and work to be furnished. Substantial completion - that date, as determined by the City Engineer, when the construction project or a specified part thereof is sufficiently completed, in accordance ---PAGE BREAK--- Standards and Specifications Section 100 Title, Scope and General Conditions Page 5 with these Standards and Specifications, so that the project or a specified part can be used for the purposes for which it is intended. Supplier - an individual, firm or corporation having a direct contract with a developer or contractor or with any subcontractor for the manufacture or furnishing of any part of the supplies and/or materials to be used at or incorporated in work at the site. Wastewater – Water which has been contaminated by human, animal, commercial, or industrial contact which is being transported to the Water Reclamation Facility. Whenever, in these Standards and Specifications, the words as ordered, as directed, as required, as permitted, as allowed or words or phrases of like import are used, it will be understood that the order, direction, requirement, permission or allowance of the City is intended. Similarly, the words approved, reasonable, suitable, acceptable, accepted, properly, satisfactory or words of like effect and import, unless otherwise specified herein, will mean approved, reasonable, suitable, acceptable, accepted, proper or satisfactory in the judgment of the City. Whenever, in these Standards and Specifications, the words City Engineer or Director of Public Works are used, it will be understood that the City employee named therein will be whoever is designated by the City Manager or whoever may be the authorized designee of the City Engineer or the Director of Public Works. All specifications ASTM, ACI, etc.) made a portion of these Standards and Specifications by reference shall be the latest edition. Throughout these Standards and Specifications, any section referenced shall be deemed to include all subsections of that section. Any portion of these Standards and Specifications that may be applicable to any other section, whether referenced or not, shall apply. 101.3. Abbreviations AASHTO - American Association of State Highway and Transportation Officials. ACI - American Concrete Institute AISC - American Institute of Steel Construction ANSI - American National Standards Institute APWA - American Public Works Association ASA - American Standards Association ASTM - American Society for Testing and Materials ---PAGE BREAK--- Standards and Specifications Section 100 Title, Scope and General Conditions Page 6 AWG - American Wire Gauge AWWA - American Water Works Association BPR - Bureau of Public Roads CDOT - Colorado Department of Transportation FCC - Federal Communications Commission IBC - International Building Code IMSA - International Municipal Signal Association IPCEA - Insulated Power Cable Engineers Association ITE - Institute of Transportation Engineers NEC - National Electrical Code as approved by the American Standards Assoc. NEMA - National Electrical Manufacturers Association NFPA - National Fire Protection Association ROW – Right-of-Way UBC - Uniform Building Code UDFCD - Urban Drainage and Flood Control District UPC - Uniform Plumbing Code UL - Underwriters Laboratories, Inc. USDA - United States Department of Agriculture 102. Scope The provisions of these Standards and Specifications shall apply to the construction, alteration, moving, removal, conversion, demolition, repair and excavation of any public improvements or common facilities specifically regulated herein except where an approved P.U.D. plan specifically states otherwise. The provisions of these Standards and Specifications apply to City contracts, developer contracts and private contracts for public facilities. ---PAGE BREAK--- Standards and Specifications Section 100 Title, Scope and General Conditions Page 7 Alterations, additions or repairs to existing improvements shall comply with all requirements of these Standards and Specifications unless specifically exempted by the City Engineer. 102.1. Alternate Materials and Methods of Construction The provisions of these Standards and Specifications are not intended to prevent the use of any material or method of construction not specifically prescribed by these procedures, provided any alternate has been approved and its use authorized by the City Engineer. The City shall require that sufficient evidence or proof be submitted to substantiate any claims that may be made regarding the alternate. The details of any action granting approval of an alternate shall be recorded and entered in the files of the City. 102.2. Modifications Whenever there are practical difficulties involved in carrying out the provisions of these procedures, the City may grant modifications for individual cases, provided that the City shall first find that a special individual reason makes these procedures impractical and that the modification is in conformity with the intent and purpose of these procedures, and provided that such modification does not lessen any design requirement or any degree of integrity. The City Engineer may allow minor modifications based on extenuating circumstances. The details of any action granting modifications shall be recorded and entered in the files of the City. 102.3. Tests Whenever there is insufficient evidence of compliance with any of the provisions of these Standards and Specifications or evidence that any material or construction does not conform to the requirements herein, the City Engineer shall require that the contractor have tests performed which will be used as proof of compliance. Test methods will be as specified by these Standards and Specifications or by other recognized test standards. If there are no recognized and accepted test methods for the proposed alternate, the City Engineer will determine test procedures. All tests will be made by an approved agency. Reports of such tests will be retained by the City. The Contractor shall furnish, without charge, all samples, tests and reports required by the City Engineer and will afford such facilities as may be necessary for collecting and forwarding them. The contractor may be required to furnish, when requested by the City Engineer, a written statement giving the origin, composition and process of manufacture of a material. 102.4. Organization, Enforcement and Interpretation The City Engineer is authorized and directed to enforce all provisions of these Standards and Specifications. The City Engineer may appoint a civil engineer, construction inspector, or other related technical officer or inspector or other employee to act in his behalf. ---PAGE BREAK--- Standards and Specifications Section 100 Title, Scope and General Conditions Page 8 Whenever any work is being done contrary to the provisions of these Standards and Specifications, the City Engineer may order the work stopped by a written notice that will be served on any persons engaged in the doing or causing of such work to be done, and any such persons will immediately stop such work until authorized by the City Engineer to proceed. These Standards and Specifications are composed of written engineering standards, materials specifications and standard drawings. The interpretation of any Section, or of any difference between Sections, when appropriate, shall be made by the City Engineer, and that interpretation shall be binding and controlling in its applications. 102.5. Liability The City Engineer, or his authorized representative charged with the enforcement of these Standards and Specifications, acting in good faith and without malice in the discharge of his duties, will not thereby render himself personally liable for any damage that may accrue to persons or property as a result of any act or by reason of any act or omission in the discharge of his duties. 102.6. Violations It shall be unlawful for any person, firm or corporation to construct, alter, repair, move, improve, remove, excavate, convert, demolish or operate any public improvements or common facilities or permit the same to be done in violation of these Standards and Specifications. 102.7. No Waiver of Legal Rights The City will not be precluded or estopped by any measurement, estimate or certificate, made either before or after the completion and acceptance of the work, from showing that the true amount and character of the work performed and materials furnished by the Contractor do not conform in fact to these Standards and Specifications, or from showing that any such measurement, estimate or certificate is untrue or incorrectly made. 102.8. Contractor’s License and Bond Any person performing work within the City of Lafayette shall obtain a Contractor's License as set forth in Chapter 30-134 of the Lafayette Municipal Code. Any contractor working in the City R.O.W. shall also post a street cut bond per City Code, Sec. 105-53.5 102.9. Work Conditions 102.9.1. Working Hours All work to be completed on the project shall be performed during regular working hours in compliance with Article VI, Noise Control, of the Lafayette Municipal Code. The ---PAGE BREAK--- Standards and Specifications Section 100 Title, Scope and General Conditions Page 9 Contractor will not permit overtime work outside regular working hours or the performance of work on Saturday, Sunday or any legal holiday without receiving written consent from the City Engineer. Work in/on streets may be restricted to 9:00 a.m. to 4:00 p.m. at the discretion of the City Engineer. 102.9.2. Emergency Work When, in the opinion of the City, the Contractor has not taken sufficient precautions for the safety of the public or the protection of the work to be constructed, or of adjacent structures or property which may be injured by processes of construction on account of such neglect, and an emergency may arise and immediate action is considered necessary in order to protect public, private, or personal interests, the City, with or without notice to the Contractor or the Developer, may provide suitable protection by causing such work to be done and material to be furnished and placed as the City may consider necessary and adequate. The cost and expense of such work and material so furnished will be borne by the Contractor or developer and will be paid on presentation of the bills. The performance of such emergency work under the direction of the City will in no way relieve the Contractor of responsibility for damages which may occur during or after such precaution has been taken. In an emergency threatening loss of life or extensive damage to the work or to adjoining property, and where the Developer or Contractor is unable to obtain special instructions or authorization from the City after diligent attempts to obtain such special instruction or authorization in sufficient time to take the necessary action, the Developer or Contractor is hereby permitted to act at his own discretion to prevent such threatening loss or damage. 102.9.3. Final Cleanup Upon completion of the work, the Contractor shall remove from the project area all surplus and discarded materials, rubbish and temporary structures and leave the project area in a neat and presentable condition. The Contractor shall restore all work that has been damaged by his operations to general conformity with the specifications for the item or items involved. The Contractor shall inspect the interior of all manholes and catchbasins within the construction limits for construction materials, dirt, stones or other debris and remove them. 102.10. Control of Work 102.10.1. Authority of Engineer The City Engineer will have the authority to stop the work whenever such stoppage may be deemed necessary. The City Engineer will resolve all questions that arise as to the quality and acceptability of materials furnished, work performed, interpretation of the plans and specifications and acceptable fulfillment of the requirements of these Standards and Specifications. ---PAGE BREAK--- Standards and Specifications Section 100 Title, Scope and General Conditions Page 10 The City Engineer may, when he deems it necessary, define the schedule and/or priority of the work to be completed on the project. The Contractor shall comply with this schedule. Any revision to the schedule must be authorized in writing by the City Engineer. The City Engineer shall resolve all questions which may arise relative to the performance of the work with respect to these Standards and Specifications. 102.10.2. Authority and Duties of Inspector Inspectors are authorized to inspect all work completed and all material furnished. Inspections may extend to all or any part of the work and to the preparation, fabrication or manufacture of the materials to be used. The inspector is not authorized to revoke, alter or waive any requirements of these Standards and Specifications. He is authorized to call the attention of the contractor to any failure of the work or materials to conform to these Standards and Specifications. Inspectors are authorized to serve a "Correction Notice" when inspection of the project reveals violation(s) of these Standards and Specifications. The inspector will have the authority to reject materials until any questions at issue can be resolved by the City Engineer. The inspector will in no case act as foreman or perform other duties for the Contractor or interfere with the management of the work done by the Contractor. Any advice that the inspector may give the Contractor will not be construed as binding upon the City Engineer or the City in any way or release the contractor from fulfilling all of the terms of these Standards and Specifications. The presence or absence of the inspector will not relieve, in any degree, the responsibility or the obligation of the Contractor. The City Engineer and inspector will, at all times, have reasonable and safe access to the work whenever it is in preparation or in progress and the Contractor will provide proper facilities for such access and inspection. 102.10.3. Contractor’s Responsibility for Work In case of suspension of work for any cause whatever, the Contractor, before leaving the job site, will take such precautions as may be necessary to prevent damage to the project, provide for normal drainage and erect any necessary barricades, signs or other facilities, at his expense, as directed by the City Engineer and required by these Standards and Specifications. 102.10.4. Removal of Unauthorized and Unacceptable Work Work which does not conform to the plans and specifications and which results in an inferior or unsatisfactory product will be considered unacceptable work. ---PAGE BREAK--- Standards and Specifications Section 100 Title, Scope and General Conditions Page 11 Unacceptable work, whether the result of poor workmanship, poor design, use of defective materials, damage through carelessness or any other cause found to exist prior to the final acceptance of the work will be immediately removed and acceptably replaced or otherwise satisfactorily corrected by and at the expense of the Developer or Contractor. This expense includes total and complete restoration of any disturbed surface to original or better than the original condition which existed before the repairs or replacement, regardless of improvements on lands where the repairs or replacement are required. 102.11. Control of Materials 102.11.1. Storage of Materials Materials will be stored so as to insure the preservation of their quality and suitability for the work. Stored materials, even though approved prior to storage, will be subject to inspection prior to their use in the work and will meet all requirements of these Standards and Specifications at the time they are used. Stored materials will be located so as to facilitate inspection. With the City Engineer's approval, portions of the right-of- way not required for public travel may be used for storage purposes and for the placing of the contractor's materials and equipment, but any additional space required will be provided by the Contractor at his expense. 102.11.2. Defective Materials Materials not conforming to the requirements of these Standards and Specifications will be considered defective and will be rejected. Rejected materials will be removed from the work site. 103. General Construction Conditions 103.1. Protection of Public and Utility Interests 103.1.1. Public Convenience and Safety Fire hydrants will be visible and accessible to the Fire Department from the street at all times. No obstructions will be placed within a 10-foot radius of a fire hydrant. Unless otherwise specified, the Contractor will give notice, in writing, to the proper authorities in charge of streets, gas, water and wastewater pipes, electric service, cable television and other conduits, railroads, poles, manholes, catchbasins and all other property that may be affected by the contractor's operations, at least 72 hours before breaking ground. The Contractor will not hinder or interfere with any person in the protection of such property or with the operation of utilities at any time. The Contractor must obtain all necessary information in regard to existing utilities, protect such utilities from injury and avoid unnecessary exposure so that they will not cause injury to the public. The Contractor shall obtain all necessary information in regard to the planned installation of new utilities and cables, conduits and transformers, and make proper provision and ---PAGE BREAK--- Standards and Specifications Section 100 Title, Scope and General Conditions Page 12 give proper notification so that new utilities and electrical equipment can be installed at the proper time without delay to the Developer or Contractor or unnecessary inconvenience to the owner. All utility crossings will be pot-holed to determine exact locations. The location of new underground utilities and electrical equipment will not be covered with pavement prior to the installation of such facilities. When the work involves excavation adjacent to any building or wall along the work, the Contractor will give property owners due and sufficient notice thereof in writing with a copy to the City. 103.1.2. Protection and Restoration of Property and Survey Monuments The Developer and Contractor shall use every reasonable precaution to prevent the damage or destruction of public or private property such as poles, trees, shrubbery, crops, fences and survey monuments adjacent to or interfering with the work, and all overhead structures such as wires or cables, within or outside of the right-of-way. The Contractor shall protect and support all water, gas, wastewater, stormwater or electrical pipes or conduits, and all railway tracks, buildings, walls, fences or other properties which are liable to be damaged during the execution of his work. He will take all reasonable and proper precautions to protect persons, animals, and vehicles from injury, and wherever necessary, will erect and maintain a fence or railing around any excavation and place a sufficient number of amber lights about the work and keep them burning from twilight until sunrise. He will employ one or more watchmen as an additional security wherever they are needed or required by the engineer. The Contractor will not prevent the flow of water in the gutters of the street and will use proper means to permit the flow of surface water along the gutters while the work is progressing. The Contractor must protect and carefully preserve all land boundary and City survey control monuments. Any monument that may be disturbed shall be referenced and replaced by a Professional Land Surveyor registered in the State of Colorado. All monuments disturbed or removed by the Contractor, through negligence or carelessness on his part or on the part of his employees or subcontractors, shall be replaced at the Contractor's expense. Replacement of any monument shall be completed in accordance with the requirements set forth in Section 103.1.4, Survey Monuments, of these Standards and Specifications, and the City Engineer shall be notified in writing. No person shall remove or disturb any grade or line stakes or marks set by the City Engineer for sidewalk installation. Developer and Contractor shall be responsible for the damage or destruction of property resulting from neglect, misconduct, or omission in his manner or method of execution or non-execution of the work, or caused by defective work or the use of unsatisfactory materials. They will restore such property to a condition similar or equal to that existing ---PAGE BREAK--- Standards and Specifications Section 100 Title, Scope and General Conditions Page 13 before such damage or injury was done, by repairing, rebuilding, or replacing it as may be directed, or they will otherwise make good such damage or destruction in an acceptable manner. Developer and Contractor will be responsible for the repair of underground pipes, wires or conduits damaged by them or their subcontractors. Developer and Contractor shall be liable for all damage caused by storms and fire and will under no circumstances start fires without first securing the necessary permits and approval of the authority having jurisdiction even though they may be ordered or required to do such burning. In burning brush, stumps or rubbish, care must be taken not to damage any standing trees, shrubs or other property. 103.1.3. Surveys Surveys will conform to Colorado Bylaws and Rules of Procedures and Rules of Professional Conduct of the State Board of Registration for Professional Engineers and Professional Surveyors, Revised. 103.1.4. Survey Monuments Permanent survey monuments (including the replacement of monuments) range points and lot pins shall be set in accordance with the requirements of Articles 51 and 53 of Title 38, Colorado Revised Statutes, and as required by the Bylaws and Rules of Procedure of the Colorado State Board of Registration for Professional Engineers and Professional Land Surveyors. 103.1.5. Use of Explosives When blasting is permitted and approved in writing by the City Engineer, the Developer and Contractor will use the utmost care to protect life and property. Signals warning persons of danger will be given before any blast. Excessive blasting or overshooting will not be permitted. The City Engineer will have authority to order any method of blasting discontinued which leads to overshooting, is dangerous to the public, or destructive to property or to natural features. Before any blasting will be done by the Contractor, a certificate of insurance, indicating special blasting coverage in the following minimum amounts, will be filed with the City Engineer: Property Damage, each accident $20,000,000.00 Public Liability, bodily injury, single limit or equivalent, each accident $20,000,000.00 103.1.6. Protection of Streams, Lakes and Reservoirs The Developer and Contractor will take all necessary precautions to prevent pollution of streams, lakes and reservoirs from fuels, oils, bitumens, calcium chloride or other harmful materials. They will conduct and schedule their operations so as to avoid or minimize siltation of streams, lakes and reservoirs. A plan for erosion protection, as required by the NPDES Regulations and/or Corps of Engineers Stormwater Rules, will be submitted ---PAGE BREAK--- Standards and Specifications Section 100 Title, Scope and General Conditions Page 14 to the City for approval before starting work and must conform to all local, state and federal regulations. Grading and erosion control permits are required. 103.1.7. Dustproofing The Contractor will take all necessary steps to control dust arising from operations connected with the work. 103.1.8. Traffic Control, Barricades and Warning Signs All construction, maintenance or utility work being completed within the public right-of- way, must have a Method of Handling Traffic (MHT) approved by the City Engineer. The MHT is a plan for guiding and handling pedestrian and vehicular traffic safely through the construction work zone. The MHT must provide safe methods for movement of pedestrians and motorists that travel through the work zone and a safe area for all workers engaged in the construction activity. The MHT shall show the location, spacing and scheduling of the usage of advance warning signs, barricades, pavement markings and other control devices. All control devices must be installed and maintained in accordance with the Manual on Uniform Traffic Control Devices (MUTCD) and the CDOT Work Zone Safety Handbook, latest editions. Requirements contained in these manuals will be strictly enforced during the progress of the work. The MHT must be job specific and prepared by a certified Traffic Control Supervisor. In order for a MHT to be approved by the City Engineer it must contain, as a minimum, a drawing showing the project area and the street(s) that may be affected by the project. The drawing shall include the following information: a. Location and spacing of properly planned traffic control devices; b. The length of time that the construction will be in progress; c. The name and phone number(s) of the Contractor's designated traffic control supervisor; d. Any special notes or information on how the traffic control operation is to be handled; e. Emergency contact name and phone number. The responsibilities of the contractor shall include the following: 1. Obtain a street closure and right-of-way construction permit from the City of Lafayette Public Works Department. 2. Provide timely notification to, and coordination with, all affected agencies, including the following: a) Lafayette Fire Department b) Lafayette Police Department c) Lafayette City Engineer d) Lafayette Public Works Department e) Utility companies f) RTD ---PAGE BREAK--- Standards and Specifications Section 100 Title, Scope and General Conditions Page 15 3. Inform occupants of abutting properties of access limitations made necessary by the work. 4. Schedule and expedite the work to cause the least inconvenience to the public. Construction or repair work will not be permitted at or in the vicinity of signalized intersections or on major streets and State Highways without advance approval of the City Engineer and CDOT as applicable. 5. Furnish, install and maintain required traffic control devices and facilities, as required throughout the life of the contract (including periods of suspension). 6. Provide flagmen when required. 7. Insure that survey crews and other employees working in or adjacent to a traveled roadway wear flagging garments as required for flagmen. 8. Provide adequate safeguards for workers and the general public. 9. Patrol the construction site as required to insure that all devices are in place and operating at all times. 10. Ensure that all traffic control devices are clean and maintained properly at all times. 11. Remove traffic control devices when they are no longer needed. Intersections and driveways will be closed for a minimum amount of time. The Contractor shall coordinate driveway closures with property owners and obtain final approval from the City Engineer. All temporary traffic lanes shall be a minimum of 10 feet wide unless otherwise authorized. In addition, lane clearance shall be a minimum of 5 feet from an open excavation and 2 feet from a curb or other vertical obstruction unless properly barricaded. Suitable surfacing must be provided for the temporary traffic lanes in work areas. When traffic is diverted from the existing pavement, temporary surfacing shall be provided as required by the City Engineer. Construction equipment not actively engaged in the work, employee vehicles and official vehicles of the agency shall not be parked in the vicinity of the work in such a manner as to further restrict traffic flow. Vehicles and equipment in continuous or frequent use may be operated or parked in the same traffic lane as the work obstruction if it is within the traffic control work zone. Construction spoil or materials may be similarly stored in this area or on the nearby parkway or sidewalk area, provided 4 feet of sidewalk is kept clear for pedestrian use. To prevent the spoil bank from occupying too great a space at its base, toe boards may be used to keep it 2 feet from the edge of the excavation on one side and 2 feet from the edge of the traffic lane on the other. 103.2. Use of City Water If the Contractor requires City water for any part of the project, he must obtain a temporary hydrant meter through the Finance Department. ---PAGE BREAK--- Standards and Specifications Section 100 Title, Scope and General Conditions Page 16 103.3. Pavement Cuts All underground utility installations crossing arterials or streets overlaid within 5 years shall be done by boring, except for emergency repairs. An exception may also be granted when a plan is submitted to overlay the entire street (block to block), or such other plan as approved by the City Engineer. If a pavement cut is required within the travel area, the Contractor will make every effort to install a permanent, hot mix, asphalt patch within 24 hours. The Contractor will place a temporary, cold mix, asphalt patch in all street cuts immediately after completing backfill and compaction if a permanent patch cannot be installed within 24 hours. The Contractor will submit a schedule for the hot mix patch installation to the City Engineer for approval in the latter case. Refer to Standard Drawing No. 100-2a and No. 100-2b for details. All pavement cuts will adhere to Chapter 105, Article III, Excavations. 103.3.1. Pavement Replacement Construction Requirements Pavement replacement for street cuts will be constructed according to the following requirements: a. Areas to be patched will be saw-cut so that horizontal and vertical edges are straight. b. Old material will be removed to a minimum depth of 6 inches or to the depth of the existing asphalt, whichever is greater. c. The excavated area will be recompacted to 95% standard proctor as per ASTM- 698 and edges cleaned prior to the application of tack coat. d. Tack coat will be applied to the edges of the excavated area prior to placement of new material. e. Hot bituminous material will be placed in the excavated area and compacted to a minimum density of 95%. f. Finished patch will be smooth and conform to the grade of the existing asphalt. g. Work area will be cleaned at the end of each working day. h. Refer to Standard Drawings 500-1 and 500-2. 103.4. Public Utility Mains Public utility mains are defined as water, wastewater and stormwater mains which service more than one property owner. Easements must be dedicated for public utility mains which extend onto or are looped through private property. 104. Inspections All construction work shall be subject to inspection by the City Engineer or his designated representative, and certain types of construction shall have continuous inspection by special inspectors. It shall be the responsibility of the person performing the work to notify the City Engineer or his authorized representative that such work is ready for inspection. Every request for inspection shall be filed at least one working day before such inspection is ---PAGE BREAK--- Standards and Specifications Section 100 Title, Scope and General Conditions Page 17 desired unless otherwise stated in these Standards and Specifications. Such request may be in writing or by telephone, at the option of the City Engineer. It shall be the responsibility of the person requesting inspections required by these Standards and Specifications to provide access to and means for proper inspection of all work. All work will be inspected by the City Engineer who will have the authority to halt construction when, in his opinion, these Standards and Specifications and/or standard construction practices are not being followed or the work is otherwise defective. Whenever any portion of these Standards and Specifications is violated, the City Engineer shall give the Contractor written notice listing deficiencies to be corrected and may order further construction to cease until all deficiencies are corrected. If the deficiencies are not corrected within the time limit specified in the notice, the City Engineer may evoke enforcement options authorized by the Lafayette Municipal Code and/or performance guarantees under which the work is being performed. The procedure for final inspection and acceptance will be as specified in the contract documents or in Section 106, Acceptance Procedures, of these Standards and Specifications. 104.1. Additional Inspections and Reinspection The City Engineer may make or require other inspections of any work as deemed necessary to ascertain compliance with the provisions of these Standards and Specifications and other provisions of the Lafayette Municipal Code. A reinspection fee may be assessed for each inspection or reinspection when such portion of work for which inspection is called is not complete or when corrections called for have not been made. This subsection is not to be interpreted as requiring reinspection fees the first time a job is rejected for failure to comply with the requirements of these Standards and Specifications, but rather as controlling the practice of calling for inspections before a job is ready for such inspection or reinspection. Reinspection fees may be assessed when the permit is not in the possession of the permit holder or his agent at the work site, when the approved plans are not readily available to the inspector, for failure to provide access on the date for which inspection is requested, or for deviating from plans accepted by the City Engineer. 105. Plans and Specifications Plans, engineering calculations, diagrams and other data shall be submitted in three or more sets, as required by the City Engineer, with each application for a permit. The City will require that plans, computations and specifications be prepared and designed by a Registered Professional Engineer, licensed to practice in the State of Colorado. ---PAGE BREAK--- Standards and Specifications Section 100 Title, Scope and General Conditions Page 18 The preparation of the as-built drawings as required in Section 106.2.2, Construction Acceptance Procedures, of these Standards and Specifications shall be based on field inspections performed under the direct supervision of the design engineer responsible for the original approved engineering construction drawings. Field inspection reports shall be submitted along with certified as-built drawings. If the design engineer responsible for the original approved engineering construction drawings is changed prior to preparing as-built drawings, the replacement design engineer shall agree in writing to accept the responsibility for final approval and acceptance of public improvements. EXCEPTION: The City Engineer may waive the submission of plans, calculations, etc., if he finds that the nature of the work applied for is such that reviewing of plans is not necessary to obtain compliance with these Standards and Specifications. 105.1. Construction Plan Requirements All construction plans will be checked for conformance with the Standards and Specifications prior to acceptance by the Public Works Department. This acceptance shall be for conformance to City design standards and other requirements; engineering design will remain the responsibility of the professional design engineer. Five sets of prints shall be signed and sealed by the registered professional engineer, licensed in the State of Colorado (in accordance with The 1973 Colorado Revised Statutes, Title 12, Article 25, Paragraph 117), responsible for the design. The cover sheet will have a City construction approval stamp. Two of the signed sets shall be returned to the design engineer, and three sets shall be kept by the City. One of the sets returned to the design engineer shall be kept on the job by the Contractor for the duration of the project. All drawings and prints shall be 24 inches x 36 inches. Should circumstances warrant changes to the accepted plans or specifications, written approval must be obtained from the City Engineer. Copies will be given to the Developer or Contractor and the design engineer. It will be the duty of the design engineer and the Contractor to record any and all changes on as-built drawings at the completion of the project in compliance with Paragraph 106, Acceptance Procedures, of these Standards and Specifications. 105.1.1. General Requirements Plans and specifications shall be drawn to scale and shall have sufficient clarity to indicate the location, nature and extent of the work proposed and show in detail that they conform to the provisions of these Standards and Specifications and all relevant laws, ordinances, rules and regulations. Each set of construction drawings shall include a Master Utility Plan (MUP). The MUP shall be a plan drawing at a reasonable scale (preferably 1 inch = 100 feet or larger) and shall show all of the water, wastewater, storm drainage and street construction to be completed under the project. The MUP shall show all of the pipe sizes, locations, connections to existing facilities and other pertinent information that would add to the overall understanding of the project. ---PAGE BREAK--- Standards and Specifications Section 100 Title, Scope and General Conditions Page 19 The following items will be shown on all plans: a. Title Block (lower right-hand corner preferred) b. Scale c. Date and revision log d. Name of professional engineer or firm e. Professional engineer's seal and signature f. Drawing number(s) g. Index on cover sheet h. Vicinity map on cover sheet i. Location map on each sheet j. Variance Statement (if necessary) The applicant is requesting a variance from the Standards and Specifications for the following: 1. (List all applicable items) Accepted by: City Engineer Date 105.1.2. Plan Details a. North arrow b. Property lines: indicate lots to be served by solid lines, other property lines dotted c. Ownership or subdivision information d. Street names and easements with width dimensions e. Existing utility lines (buried) location and depth of water, gas, telephone, storm drain, irrigation ditches, wastewater lines, and other pertinent details houses, curbs, water courses, etc.) 105.1.3. Profile Details a. Vertical and horizontal grids with scales b. Ground surface existing (dotted) and proposed (solid) c. Existing utility lines where crossed d. Bench marks (City Datum) e. Existing manhole invert and rim elevations 105.1.4. Water Supply Construction Details In addition to the above general plan and profile details, all water supply construction plans will include the following items: a. Proposed water mains Size Length Materials and types of joints Location dimensions b. Fittings ---PAGE BREAK--- Standards and Specifications Section 100 Title, Scope and General Conditions Page 20 Tees Crosses Reducers Bends Plugs Blow-off c. Valves d. Fire Hydrants e. Plan, profile and complete details for off-site transmission mains, pump stations, special valves, and vaults, tanks, etc. f. Standard bedding detail (cross-section) 105.1.5. Wastewater Construction Details In addition to the general plan and profile details, all wastewater construction plans will include the following: a. Proposed wastewater mains Diameters Materials Gradients Length between manholes b. Proposed manholes and cleanouts Stationing and other number designation Elevation of inverts in and out of manhole Elevation of manhole rim c. Location control dimensions d. Manhole stub-outs e. Proposed future extensions f. Proposed wye and riser connection for services g. Proposed service connections or stub-ins h. Proposed underdrain i. Standard bedding cross-section j. Proposed concrete encasement k. Proposed cut-off walls 105.1.6. Grading and Drainage Plan In addition to the above general plan and profile details, all grading and drainage plans will include the following: a. Drainage area plan; an overall plan of the area under study showing: North arrow Contours (maximum 2-foot intervals) Location and elevation of City bench marks Property lines Boundary lines (counties, districts, tributary area, etc.) Streets and street names and approximate grades ---PAGE BREAK--- Standards and Specifications Section 100 Title, Scope and General Conditions Page 21 Subdivision (name and location by section) Existing irrigation ditches Existing drainage ways including gutter flow directions Drainage sub-area boundaries Easements required Proposed curbs and gutters and gutter flow directions Proposed cross pans and flow directions Proposed piping and open drainage ways Path of 100-year storm runoff flows Critical minimum finished floor elevations for protection from 100 year runoff Proposed inlet locations and inlet sizes b. Proposed pipes Plan showing stationing Profile Size, between manholes and type Grades Inlet and outlet details Manhole details (station number and invert elevations) Typical bedding detail c. Proposed open channels Plan showing stationing Profile Grades Typical cross section Lining details d. Proposed special structures (manholes, headwalls, trash gates, etc.) Plan Elevation Details of design and appurtenances e. The grading and drainage plan shall conform to the final drainage report as specified in Section 1100. 105.1.7. Street Construction Details In addition to the above general plan and profile details, all street construction plans will include the following: a. Existing irrigation ditches to be removed or piped b. Proposed curb, gutter and sidewalk c. Proposed crosspans including flow direction d. Storm drainage facilities e. Location and elevation of City bench marks f. Horizontal curve data, with radii, tangents, points of curvature intersection and tangency g. Typical section of street construction showing structure and dimensions h. Stations and elevations of radius points (back of curb) i. Proposed profile of flow lines of gutter ---PAGE BREAK--- Standards and Specifications Section 100 Title, Scope and General Conditions Page 22 j. Stations, and elevations of vertical curve P.C., P.I. and P.T. k. Percent slope of tangent lines l. Limits of construction m. Show sufficient existing or future construction to assure continuity of construction n. Stations and elevations of drainage facilities and other structures The Area Grading Plan must follow the approved Drainage Plan. 105.1.8. Erosion Control Plan Details All subdivisions shall include an erosion control plan as specified in Section 402, Erosion Control Plan, of these Standards and Specifications. Erosion control plan drawings will use the same base map as that for the Drainage Plan and will include, at a minimum, the following information: a. A general location map with sufficient detail to identify drainage flow entering and leaving the development and general drainage patterns. b. Major construction development, irrigation ditches, existing detention facilities, culverts, stormwater systems) along the path of drainage. c. Basins and divides identified with topographic contours. d. Specifications and details for erosion control measures. e. A transition grading/drainage plan for construction activities which are phased or sequenced. All residential developments will required a transition grading plan. 105.1.9. Easement Widths Water, wastewater and stormwater easements shall be a minimum of 20 feet in width for buried utility lines up to 5 feet deep. For utility lines deeper than 5 feet, the easement width shall be calculated according to the following formula: twice the trench depth plus twice the pipe diameter in feet or 20 feet, whichever is greater. 105.1.10. Specifications and Documentation The following items will also be included with submitted construction plans: a. Reference on plans to City Standards and Specifications b. Reference on plans to other agency standards and specifications that are required or proposed c. Where reference to other commonly available standards and specifications will not suffice, copies of specifications are to be provided. d. Copies of written approval from other affected agencies as required. e. Soils and other test data and design calculations for street structural sections, drainage facilities and other appurtenances as required. f. Soils resistively tests at pipe depth. 105.2. Engineering Reports All engineering reports shall include on the title page: 1) the type of report (preliminary or final); 2) the project name; 3) the preparer’s name, date, and firm; and 4) P.E. seal of preparer. ---PAGE BREAK--- Standards and Specifications Section 100 Title, Scope and General Conditions Page 23 105.2.1. Preliminary Reports The following preliminary reports must accompany all PUD and preliminary plat applications: Utility Report (2 copies) Drainage Report (2 copies) Traffic Analysis Report (2 copies) Geotechnical Studies (2 copies) Additional reports as required by the Lafayette Municipal Code 105.2.2. Preliminary Utility Report Requirements Preliminary utility reports will include the following information and data as a minimum: 1. Wastewater Lines a) Layout/ Connection to Wastewater System b) Average and Peak Flow Calculations 2. Water System a) Layout/ Connection with City Water b) Potable Water Demand (peak and average) 105.2.3. Preliminary Geotechnical Report Requirements Geotechnical and soils investigation studies are required for foundation design and pavement design. These two categories may be combined into one report when the purpose of the investigation includes both facets of design. A preliminary geotechnical report shall include the following information at a minimum: 1. General Information a) Past and present land uses and features b) Proposed use of the land when developed c) Surface drainage characteristics d) A general geologic report on the area and a discussion of the soil profiles and subsurface features e) Potential slope instability 2. Unusual Land Uses/Conditions a) Report which identifies all unusual land uses such as landfills, open dumps, wetlands, leach fields, areas of natural springs, faults, mines, etc. These shall be presented in a written and graphical format of suitable scale. 3. Pavement Design 105.2.4. Preliminary Traffic Analysis Report Required information for the preliminary traffic report shall include, but not be limited to the following: 1. Land use, site and study area boundaries ---PAGE BREAK--- Standards and Specifications Section 100 Title, Scope and General Conditions Page 24 2. Existing and proposed site uses 3. Existing and proposed roadways and intersections 4. Existing and proposed roadways and intersection capacities and volumes 5. Trip generation and design hour volumes 6. Trip distribution 7. Trip assignments 8. Existing and projected (20-year future) traffic volumes 9. Levels of service of all affected intersections for the design hour (with development and future) 10. Recommendation for street layout and modifications 105.2.5. Preliminary Drainage Report Drainage report calculations and supporting data required as set forth herein shall be prepared in accordance Section 1500. 105.2.6. Final Engineering Reports The following final reports must accompany all site development plan and final plat applications: Utility Report (2 copies) Drainage Report (2 copies) Traffic Analysis Report (2 copies) Geotechnical Studies (2 copies) Additional reports as required by the Lafayette Municipal Code or City Engineer 105.2.7. Final Utility Report Final utility reports will include the following information and data as a minimum: 1. Wastewater Facilities a) Layout and connection to city wastewater system b) Average and peak flow calculations c) Maximum and minimum slope and velocity d) Available existing capacity 2. Water a) Layout and connection with City water b) Potable water demand (peak and average) c) Fire flow demand d) Peak instantaneous demand and meter sizing e) Available pressure and capacity f) Irrigation water demand 105.2.8. Final Traffic Analysis Report The final traffic analysis report shall include, but not be limited to the following: a) Land use, site and study area boundaries b) Existing and proposed site uses ---PAGE BREAK--- Standards and Specifications Section 100 Title, Scope and General Conditions Page 25 c) Existing and proposed roadways and intersections d) Existing and proposed roadways and intersection capacities and volumes e) Trip generation and design hour volumes f) Trip distribution g) Trip assignments h) Existing and projected traffic volumes (20-year future) i) Critical lane capacity analysis, where required j) Traffic signal analysis including warrant analysis and progression analysis with existing and proposed signal locations k) Levels of service of affected intersections for the design hour l) Future traffic impact analysis i) Short term horizon - one year after occupancy ii) 20-year planning horizon (DRCOG 20-year planning horizon) m) Traffic signage and striping plan n) Compliance/deviations from the City’s latest transportation master plan o) Recommendation for project-related and future traffic improvements 105.2.9. Final Geotechnical Report Geotechnical and soil investigation studies are required for foundation design and pavement design. These two categories may be combined into one report when the purpose of the investigation includes both facets of design. A subsurface investigation for foundation and/or pavement design shall include the following information and data as a minimum: 1. General Information a) Past and present land uses and features b) Proposed use of the land when developed c) Structure type d) Groundwater e) Surface drainage characteristics f) A general geologic report on the area and a discussion of the soil profiles and subsurface features g) Potential slope instability 2. Investigation Details a) Type of equipment used in obtaining data b) Date of drilling c) Boring logs which show the elevation of the existing ground, the elevation of the top of each soil stratum encountered and the soil classification of each stratum encountered, the water level at the time of boring and the level at a later date and standard penetration test results for each soil stratum. Each hole shall be referenced to a fixed benchmark. d) A sketch of the tested area accurately showing the locations of the borings. 3. Site Conditions/Foundation Design a) Specific information including swell potential of the soil and the effect on foundations. ---PAGE BREAK--- Standards and Specifications Section 100 Title, Scope and General Conditions Page 26 b) A recommendation as to foundation types and any special procedures that may pertain to construction. c) The effect of ground water on construction and methods to deal with any problems which may exist. d) Recommended allowable soil bearing pressures and unconfined shearing strength. e) Methods of prevention of swell and shrinkage of expansive soils and minimizing their effect on structures. f) Natural moisture content of the soil strata. g) Specifications for any unusual or special construction materials required. 4. Unusual Land Uses/Conditions a) Report which identifies all unusual land uses such as landfills, open dumps, wetlands, leach fields, areas of natural springs, faults, mines, etc. These shall be presented in a written and graphical format of suitable scale. 5. Pavement design alternatives 105.3. Final Drainage Report Drainage report calculations and supporting data required as set forth herein shall be prepared in accordance with Section 1500. 106. Acceptance Procedures 106.1. General Conditions Prior to requesting final inspection or construction acceptance of the work: a. All temporary structures, debris, mud and waste materials shall be removed from all public property. b. A complete and accurate set of as-built drawings shall be submitted to the City Engineer for approval. Changes to the original design drawings must be supported by documentation which contains the signature and seal of a Colorado Registered Professional Engineer. c. All relevant testing certifications and documentation shall be submitted to the City Engineer for approval. All required certifications must contain the signature and seal of a Colorado Registered Professional Engineer. d. All other supporting documentation as may be required shall be submitted to the City Engineer for approval. 106.2. Construction Acceptance Procedures for Subdivision Public Improvements 106.2.1. Final Inspection Upon completion of all construction and prior to requesting City approval, the contractor and/or owners representative should conduct their own inspection and make all necessary corrections. An inspection checklist may be obtained from the City’s Engineering Department. ---PAGE BREAK--- Standards and Specifications Section 100 Title, Scope and General Conditions Page 27 When the improvements to be accepted are complete and ready for final inspection, the owner shall contact public works. The City Engineer will then schedule a date and time for final inspection with members of the City staff within two weeks of request. Within two weeks after the final inspection, a list of deficiencies will be prepared by the City Engineer and presented to the Developer. Within one week of receipt of this list, the Developer shall submit a satisfactory time schedule for correction of the deficiencies. The deficiencies must be corrected within 45 days of the receipt of the list. After the Developer and the Contractor have corrected the deficiencies, the developer must inform the City that repairs have been made, and a follow-up final inspection will be scheduled. The time schedule noted above may be extended only under special circumstances with the written approval of the City Engineer. Should the deficiencies not be corrected in the time period outlined herein, the City has the right to prepare another list of deficiencies and/or draw upon the performance guarantee as specified in the development agreement to complete the improvements. There may be partial releases of letters of credit after all utilities are in place and a street is paved except for the top lift. In no case will the amount of surety be released to less than 10% of the original total plus the cost of the remaining work. 106.2.2. As-Built Drawings After the Public Improvements have passed the final, the Developer shall request Public Improvements Acceptance. The following items must be submitted with the request: a. A full set of as-built, permanent, reproducible Mylars (4 mil thickness, double matted reverse film, 24 inches x 36 inches). All of the as-built drawings shall contain the following statement: This plan and the information contained hereon accurately represents the As- Built condition of the improvements shown as of ___(date) By: P.E. No. John Doe b. A diskette of as-built drawings in AutoCAD 14 or later) conforming to the City’s required layer/naming system.. c. Any other items required under the subdivision agreement. The City will review the application for accuracy and completeness. A minimum of 10% of the "total improvement cost" shall be held by the City during the 3-year warranty period after construction acceptance, unless otherwise approved by City Council or otherwise stated in the subdivision agreement. ---PAGE BREAK--- Standards and Specifications Section 100 Title, Scope and General Conditions Page 28 106.2.3. Repairs and Replacement Upon acceptance by the Public Works Director or the City Engineer, the maintenance of the new improvements and facilities will become the responsibility of the City, except for repairs and replacements which, in the opinion of the City Engineer, shall become necessary during a period of three years after the final acceptance date. If, within ten days after the Developer has received written notice from the City Engineer requesting repairs or replacements, the Developer has not undertaken to make the repairs or replacements, the City may make the repairs and replacements and draw upon the Developer's performance guarantee as specified in the subdivision agreement. See City Code Section 26-19-18. 106.2.4. Warranty Inspection Approximately three years following acceptance, the Developer must request an inspection for consideration of completion of the warranty period. Following inspection, a list of deficiencies will be prepared. After repairs have been made, a follow-up inspection must be requested. The warranty period is not over until all warranty repairs have been made and accepted. . 106.3. Acceptance Procedures for Public Improvements Contracted by the City The inspection and acceptance procedures for public improvements contracted by the City are specified in the contract documents. 106.3.1. Repairs and Replacement The maintenance of the new improvements and facilities contracted by the City will become the responsibility of the City, unless detailed otherwise in the development agreements, except for repairs and replacements which, in the opinion of the City Engineer, shall become necessary during a period of three years after the final acceptance date. ---PAGE BREAK--- Standards and Specifications Section 200 Water Supply Facilities Page 1 Section 200 Water Supply Facilities (updated Dec 2011, meters) 200. WATER SUPPLY FACILITIES 3 200.1. GENERAL 3 200.2. PERMITS 3 200.3. MAINTENANCE OF TRAFFIC 3 201. WATER MAIN CONSTRUCTION 3 201.1. . 3 201.2. ALIGNMENT AND 3 201.3. PROTECTION OF EXISTING UNDERGROUND 4 201.4. INTERRUPTION OF 4 201.5. PIPE 4 201.6. THRUST BLOCKING, RESTRAINED JOINTS AND 5 201.7. SETTING VALVES AND HYDRANTS 5 201.8. TRENCHING 6 201.9. BACKFILL MATERIALS 7 201.10. BACKFILL 8 201.11. MAINTENANCE OF BACKFILL 8 201.12. COMPACTION 8 201.13. FILLING AND VENTING THE 9 201.14. DISINFECTION AND FLUSHING OF MAINS 9 201.15. 9 202. STEEL CASING AND CARRIER PIPE 9 203. TEST STATIONS 204. SPECIAL CONDITIONS 205. WATER SERVICE LINE CONSTRUCTION 205.1. GENERAL 205.2. SERVICE LINE TAPPING 205.3. INSPECTION 206. WATER FACILITIES PARTS LIST DRAWINGS 200 Water Line Bedding Detail 200-1 Air Vacuum Relief Valve 200-2 Temporary Blowoff 200-3 Fire Hydrants Mains and Valves 200-4 Tracer Wire 200-5 PRV in a Vault (Plan) 200-6 PRV in a Vault (Section) 200-7 Vent Pipe 200-8 Polyethylene Wrap 200-9 Insulators 200-10a Residential Service with Meter and Pit (under 1-1/2”) 200-10b Meter Pit 200-11 Thrust Blocking 200-12 Horizontal Thrust Blocking Areas 200-13 Vertical Thrust Block Volumes ---PAGE BREAK--- Standards and Specifications Section 200 Water Supply Facilities Page 2 200-14 Pipe Line Test station 200-15 Residential Vent Assembly ---PAGE BREAK--- Standards and Specifications Section 200 Water Supply Facilities Page 3 Section 200 Water Supply Facilities 200. Water Supply Facilities 200.1. General Provisions All water main construction within the City and all water service line construction connecting to the City's water mains will be done in accordance with these Standards and Specifications and the accepted plans and will apply to new water system construction as well as to repairs of existing facilities. When special conditions are encountered, or deviations from these Standards and Specifications are required by the City Engineer and such changes are in the best interests of the City, the decision of the City Engineer will be final. 200.2. Permits Required Construction will not begin until the water main plans have been accepted by the City Engineer. A pre-construction meeting with the City Inspector and City Engineer, the Developer and the Contractor will be scheduled and completed prior to the commencement of any construction. The City Engineer will be notified two working days (48 hours) before the planned construction is to begin. A separate permit will not be issued for this work. The development agreement will be the controlling document. 200.3. Maintenance of Traffic Work in existing streets will maintain two-way traffic unless there is a special traffic control plan approved by the City Engineer. See Section 103.1.8, Traffic Control, Barricades and Warning Signs of these Standards and Specifications.. 201. Water Main Construction 201.1. General All work will conform to applicable portions of AWWA C605, Installation of PVC Water Mains, and to the pipe manufacturer's installation instructions except as modified by these specifications. 201.2. Alignment and Grade Alignment and grade of the pipe and the location of fittings, valves, and hydrants will be as shown on the approved drawings. The required minimum depth of cover between the top of the pipe barrel and the finished street grade is 4 feet 6 inches. As-built drawings of pipe alignment and grade, verified by a Professional Engineer, will be furnished to the City Engineer. ---PAGE BREAK--- Standards and Specifications Section 200 Water Supply Facilities Page 4 201.3. Protection of Existing Underground Utilities The Contractor will be held responsible for the protection of public improvements as stated in Section 103.1, Protection of Public and Utility Interests, of these Standards and Specifications. It will be the Contractor's responsibility to replace all public improvements so damaged at his own expense. 201.4. Interruption of Services Interruption of services shall be kept to a minimum and if necessary shall be accomplished in accordance with Section 103.1, Protection of Public and Utility Interests, of these Standards and Specifications. 201.5. Pipe Installation Proper equipment, tools and facilities will be provided and used by the Contractor for safe and convenient performance of the work. All pipe, fittings, valves and hydrants will be carefully lowered into the trench piece by piece so as to prevent damage to pipe materials and to protect coatings and linings. Under no circumstances will pipe or fittings be dropped or dumped into the trench. Any pipe or fittings that are dumped will be removed from the work site and will not be used. All pipe and fittings will be carefully examined for cracks and other defects while suspended above the trench, immediately before installation in final position. The groove in the bells of ductile iron pipe will be full and continuous or the pipe will be rejected. Defective pipe or fittings will be removed from the job site within 24 hours. All foreign matter or dirt will be removed from the interior and ends of pipe and accessories before they are lowered into position in the trench. Every precaution will be taken to prevent foreign material, including trench water, from entering the pipe. If the pipe-laying crew cannot lower the pipe into the trench and into place without getting earth into it, the representative of the City Engineer will require that before lowering the pipe, a heavy, woven canvas bag of suitable size be placed over each end of the pipe and left there until the connection is made to the adjacent pipe. During construction, no debris, tools, clothing, gravel or other foreign materials will be placed in the pipe. During construction the Contractor will provide and maintain adequate equipment to properly remove and dispose of all water entering the trench or any other part of the work. When buried, all ductile iron pipe fittings and appurtenances will be protected with a 10-mil thick polyethylene film wrap. Miscellaneous steel or other ferrous pipe for blow-offs, etc. will be similarly protected. As each length of pipe is placed in the trench, the circular rubber gasket will be lubricated and installed according to the manufacturer's recommendation. The plain end will be centered in the socket with care used to keep the joint from contacting the ground. The pipe will then be properly seated and brought to the correct line and grade. After installation of the polyethylene protective wrap as described above, pipe will be secured in place by installation of backfill or bedding material, tamped under and along it up to the springline of the pipe. ---PAGE BREAK--- Standards and Specifications Section 200 Water Supply Facilities Page 5 At times when pipe-laying is not in progress, the open ends of pipe will be closed by means of a watertight plug. Cutting of pipe for inserting valves, fittings, or closure pieces will be done in a neat and workman-like manner without damage to the pipe or lining and so as to leave a smooth end at right angles to the axis of the pipe. Pipe ends will be smooth and beveled with a file or other tools according to the pipe manufacturer's recommendations. The City Engineer shall be notified at least one working day (24 hours) in advance of when pipe is to be laid in any trench. 201.6. Thrust Blocking, Restrained Joints and Fittings No pipes will be covered until they have been inspected by a representative of the City. Thrust blocks or mechanical restraints shall be used at all valves, bends, fittings and dead ends. Thrust blocking shall be in accordance with Standard Drawings 200-11 through 200-13. Care shall be taken not to block outlets or to cover bolts, nuts, clamps or other fittings or to make them inaccessible. A bond breaker shall be placed between the pipe and the thrust block to aid in ease of future removal. The thrust block shall bear against undisturbed earth. Mechanical restraints shall be required if a thrust block cannot bear against undisturbed earth. All forming for thrust blocks and anchors will be done by bulkheading around the shape of the thrust block or anchor with burlap or reinforced paper sacks filled with sand or earth. Wood forms shall not be used. Newly placed thrust blocks shall be allowed to set, undisturbed, for a minimum of 24 hours prior to any backfilling, tamping or compacting. 201.7. Setting Valves and Hydrants Immediately prior to the installation of a valve or hydrant, the following operations will be performed. The valve or hydrant will be carefully inspected. The interior will be thoroughly cleaned. The valve or hydrant will be operated as many times as necessary to determine that all parts are in proper working order with the valve seated properly and the hydrant drain valve operating properly. Valves and hydrants will be set plumb, in a vertical position and securely braced in place. Each hydrant will have a 6-inch gate valve on the inlet line. The valve shall be firmly anchored to the tee. Where hydrants are connected to mains larger than 8 inches, the gate valve will have a restrained connection directly to the tee off the main. Hydrants will be set with the bury line at the established finished grade and with hose nozzles parallel to the curb with the pumper nozzle facing the curb and at least 6 inches behind the curb or sidewalk. Valves will be provided with valve boxes centered and plumb over the operating nut of the valve. The boxes will be supported to prevent the transmission of any shock or stress to the ---PAGE BREAK--- Standards and Specifications Section 200 Water Supply Facilities Page 6 valve. Valve boxes will be maintained in this position during backfilling and covers will be set to finished position during backfilling. Valve box covers will be set to finished grade but may be first left just below the subgrade level to prevent damage during street construction and later adjusted to grade at the time of paving. Hydrants will be provided with a drainage pit with 9 square feet of surface area and 2 feet of depth below the barrel of the inlet. Pits will be backfilled with 1½ inch washed, crushed rock to a level 6 inches above the barrel drain hole. A concrete thrust block will be provided at the bowl of each hydrant as shown on Standard Drawing No. 200-3 and will be placed so as to not obstruct the barrel drain hole. Hydrants and valves will be backfilled to the ground surface as specified in Section 201.9, Backfill Materials, of these Standards and Specifications. 201.8. Trenching This work shall consist of furnishing all labor, materials, tools and equipment for trenching, bedding, backfill and compaction for all underground utilities as specified herein and shown on the accepted plans. The excavation shall be made to lines and grades shown on the accepted plans and as established by the City Engineer. Except where shown otherwise on the accepted plans and except where the City Engineer gives written permission to do otherwise, all trench excavation shall be made by open cut to the depth required to construct the pipelines as shown on the accepted plans. All excavation shall be unclassified. When excavating in concrete or asphalt areas, the limits of the trench shall be string-lined and the surface cut in a vertical plane by sawing. During construction, should the vertical edges ravel, they shall be trued to a vertical plane to a point 6 inches outside the limits of excavation prior to placing the resurfacing material. The maximum size of street cut in existing major arterial or collector streets will be 8 feet square. The remainder of the line under the finished street will be installed by pushing or boring, unless otherwise approved in writing by the City Engineer. Surface materials such as concrete and asphalt shall be disposed of independently of the underlying soil; base course and gravels are to be salvaged to stockpile, protected from contamination and reused for backfill whenever practical. Unsuitable materials (unacceptable for use as backfill) shall be disposed of by the contractor in accordance with Section 1003.3, Disposal, of these Standards and Specifications. Excavation will not be permitted to advance more than 150 feet ahead of pipe laying and 200 feet in advance of the backfill operations. No trench will be left open overnight without written permission of the City Engineer. The contractor shall provide and maintain adequate equipment to properly remove and dispose of all surface or ground water entering the trench. Water shall be disposed of in a suitable manner without damage to adjacent property or without being a nuisance to public health and convenience. The use of any wastewater lines to dispose of trench water will not ---PAGE BREAK--- Standards and Specifications Section 200 Water Supply Facilities Page 7 be permitted. The trench shall be dry at all times during pipe installation and so maintained until the joining operation is complete. 201.9. Backfill Materials Suitable backfill shall be as defined in Section 1004.1 of these Standards and Specifications. In addition, all wood or other organic material and deleterious substances must be removed. Clay and similar material with a liquid index in excess of 35 and a plasticity index in excess of 6 (determined in conformity with AASHTO T 89 and T 90) will not be considered suitable for backfilling in trenches located in improved streets, roads, highways and thoroughfares. When the excavated material is unsuitable for compaction, other material must be provided that will meet the requirements of the following table: TABLE 200-3. BACKFILL MATERIAL FOR PIPELINES AND SERVICE LINES Sieve Size Total Percent Passing by Weight 2 inch 100 No. 4 30 – 100 No. 50 10 – 60 No. 200 5 - 20 Also, flow-fill meeting the following requirements may be used to backfill pipelines and service lines when specified in the contract. Mix: Minimum 24-hour strength: 10 psi Maximum 28-day strength: 60 psi Maximum aggregate size: 1 inch Cement: Type I-II (Ideal ASTM C 150) Slump: 6 inch minimum, 8 inch maximum 200-4. MIX PROPORTIONS (PER CUBIC YARD OF CONCRETE) Pounds Absolute Volume Cement (0.45 sack) 42 0.21 ft³ Water 325 (39 gallons) 5.20 ft³ 1” Aggregate (ASTM C33, Size No. 57) 1,700 10.17 ft³ Sand – ASTM C33 1,845 11.24 ft³ Air (Entrained ) 1.5% 0.41 ft³ Theoretical Unit Weight: 143.7 lbs/yd³ @ 1.5% air ---PAGE BREAK--- Standards and Specifications Section 200 Water Supply Facilities Page 8 Theoretical Yield: 27.23 ft³ @ 1.5% air % Sand of Total Aggregate: 52% Note: Aggregate weights are based on the materials being in a saturated surface-dried condition. Materials used above the subgrade level will conform to the requirements for sub-base and base course materials as defined in Section 500, City Street Construction, of these Standards and Specifications. Any bracing installed to prevent cave-ins will be withdrawn in a manner that will maintain the desired support during the backfill operations. Driven sheet pilings will be cut off at or above the top of pipe, and the portion below the cut-off line will be left in the ground. During construction, the trench backfill shall be topped out with not less than 9 inches of CDOT Class 5 or 6 aggregate base course and maintained free of chuckholes, ruts and loose rock until permanent asphalt surfacing is in place. 201.10. Backfill Compaction Trench backfill will be placed in loose 6 inch lifts and each lift thoroughly consolidated by tamping, vibrating, or a combination thereof, until the density is equal to 95% maximum dry density based on a site specific standard proctor, ASTM-D-698. Pipes, culverts, wastewater lines and other miscellaneous structures outside the roadway prism or sidewalk and not subject to traffic loads or heavy loads for a period of 2 years shall be backfilled in layers as described above but shall be compacted to approximately 85% of the maximum density. Consolidation shall be obtained by the use of hand tampers having a minimum weight of 20 pounds and a facial area in excess of 24 square inches. Hydrohammers shall not be used until the trench backfill has been placed and compacted to within 3 feet of the finished grade by the lift method. Large roller, tractor-drawn equipment or hydrohammers shall not be used within 18 inches of rigid pipe or 36 inches of flexible pipe. Flooding or jetting of trenches will not be permitted unless specific written approval is obtained from the City engineer. 201.11. Maintenance of Backfill All backfill shall at all times during construction be maintained to the satisfaction of the City Engineer. Access across trenches for driveways and streets shall be maintained free of hazards to traffic or pedestrians. 201.12. Compaction Testing The compaction of the bedding and all types of backfill shall be tested at a rate of at least one test per 200 cubic yards of fill material or portions thereof and at least one test per 250 feet, whichever controls. The testing shall be at various depths and locations. The ---PAGE BREAK--- Standards and Specifications Section 200 Water Supply Facilities Page 9 City Engineer may require additional testing around structures, manholes, valve boxes, etc. The Contractor will also have tests provided to the City for water and/or wastewater service lines as directed by the City Inspector. Initial test results shall be submitted to the City Engineer within 24 hours of the test or on the next working day. Compaction testing shall be performed by private engineering or geotechnical firms at the Contractor’s expense. Compaction testing shall be performed by a qualified technician who works under the direct supervision of a Registered Professional Engineer. Final soils compaction reports shall be prepared and signed by a Registered Professional Engineer who is registered in the State of Colorado and who is qualified to prepare such reports. Reports shall be submitted to the City Engineer within one week of the test. 201.13. Filling and Venting the Line All valves will be operated by the City Public Works Department. The line will be slowly filled with water and all air expelled from the pipe. Care will be taken that all available hydrants (including hydrant gate valves), air and vacuum relief valves and other vents are open during the filling of the line. Where hydrants or other vents are not available in the line, the Contractor will make whatever taps are required for venting purposes. The rate of filling the line will not exceed the venting capacity. 201.14. Disinfection and Flushing of Mains Disinfection and flushing will be done in accordance with the requirements of the Colorado Department of Health and the procedure set forth in AWWA C601, Standard for Disinfecting Water Mains. Required chlorine residual is 100 ppm. The Contractor will neutralize the chlorine solution before releasing the water. No water mains will be placed in service or tapped until a bacteriological test has been passed. 201.15. Leakage Pressure and leakage tests will be conducted according to the applicable sections of AWWA C600 to a pressure of 150 pounds per square inch at the low point of the section being tested. The maximum length of line to be tested shall be 1,000 feet, at the discretion of the City Engineer. All joints and connections are to be watertight within tolerances allowed by the specifications in AWWA C600. Any leakage discovered through observation or tests will be located and made watertight by the Contractor. Pressure and leakage tests will not be conducted until the line has passed all required disinfection tests. 202. Steel Casing and Carrier Pipe Installation Steel casing and carrier pipe shall be installed in accordance with Section 300.13, Steel Casing and Carrier Pipe Installation, of these Standards and Specifications. ---PAGE BREAK--- Standards and Specifications Section 200 Water Supply Facilities Page 10 203. Test Stations Test stations shall be provided for cross-country mains with no hydrants or service connections. 204. Special Conditions Subsurface Investigation - Prior to the connection of any planned utility line to an existing line, the contractor shall expose the existing utility at the points of connection in order to verify the elevations and materials of construction. The City Engineer shall be notified a minimum of two working days before such an investigation is performed. The Contractor shall also expose utilities as they cross each other to allow for verification of elevation and materials of construction. The City Engineer will evaluate this information and provide revisions, if required, within three working days of the completion of the investigation. Telephone Lines - Where underground telephone lines are encountered that were not shown on the accepted plans, they shall be relocated as directed by Qwest and in accordance with its specifications. The contractor shall coordinate this work with all other phases of construction to avoid further conflicts. Gas and Electric Lines - Where underground gas and electric lines are encountered that were not shown on the accepted plans, they shall be relocated as directed by Xcel and in accordance with its specifications. The contractor shall coordinate this work with all other phases of construction to avoid further conflicts. 205. Water Service Line Construction 205.1. General All water service line locations shall be permanently marked (etched, cut, stamped) on the curb with a symbol. All service line stub-ins will extend behind the sidewalk and behind any other utilities, such as gas and electric lines. Water service shall be in a separate trench and shall be a minimum of 10 feet from the wastewater service line. The water service line shall be a minimum of 18 inches above any wastewater line crossing. The water service line at the curb stop shall be no deeper than 5 feet 6 inches. Water service lines shall not be located under a driveway unless approved by the City Engineer. 205.2. Service Line Tapping All service line taps shall be wet taps. Shut down of any portion of the water system will only be allowed when uncontrolled circumstances do not permit a wet tap. Any shut down of the water system must be approved in writing by the City Engineer. Tapping the main for service lines should be through double strapped bronze saddles. Notification must be given to the Public Works Department two working days in advance of the tap in order to provide ample time to schedule the inspection. The tap may be installed ---PAGE BREAK--- Standards and Specifications Section 200 Water Supply Facilities Page 11 by a contractor or plumber licensed by the City who specializes in the installation of water taps. 205.3. Inspection All utility inspections must be scheduled during regular working hours a minimum of two working days (48 hours) in advance. All inspections must be scheduled by calling the inspector at [PHONE REDACTED]. All meter sets must be scheduled through the Finance Department by calling [PHONE REDACTED]. All installations by Contractors must meet these Standards and Specifications. Unnecessary recall inspections or meter installations are subject to a fee per occurrence. Out-of-city inspections require 72 hours notice. 206. Water Facilities Parts List See table following. ---PAGE BREAK--- Pipe PVC C900 Class 200 (DR 14) C905 DR 25 with static pressure < 100 psi C905 DR 18 with static pressure > 100 psi PVCO C909 Class 200 Hydrant Pipe Same as line pipe, PVC for replacement work. Pipe Fittings Epoxy coated DIP, MJ Tracer Wire 14 ga. Stranded Tracer Tape 2” Detectable Tracer Wire Box Handley T2PS3E Hydrant Spec. 1 1/2 In. Pentagon Operating Nut (Open Left), Two 2 1/2 In. Hose Nozzles (nst), One 4 ½ In. Pump (nst), 6 In. MJ Shoe Red. Approved Hydrants Mueller (MUCO A423-501147), (423-50069) Waterous (WP 250) Valves (Open Left) US PIPE AWWA C-509 CLOW RSGV MUELLER AFC Valve Boxes Tyler 6860 Series w/#160 Base (Denver) Curb Boxes Tyler 6500 Series (95E) End Connections Compression Corp. Stops A.Y.McDonald (4701BT) Mueller (B25008) Ford (FB1000G Series) ---PAGE BREAK--- Curb Stops A.Y.McDonald (6100T) Mueller (B25209) Ford (B44G Series) Service Saddles McDonald 3801,02,05,08 (PVC) Ford S90(PVC) Mueller H13000 (PVC) McDonald 3825,26 (DIP) Ford 202B(DIP) Mueller BR2B (DIP) James Jones J979 (AC) Ford 202B(AC) Mueller BR2B (AC) Meter Pits 20X24X48 DFW (HB) 20X24X48 Midstates (white) Meter Box Covers Tyler 148548 TR w/frost lid Drilled 1-7/8” Ford W32 T Castings M-70 Coppersetters Compression with locking wing on inlet. ¾” → V80W-44-33-G (with 7.5” lay length) Residential Meters (Ford) ¾” → V83W-44-33-G (with 9.0 lay length) 1” → V84W-44-44-G 1.5” → VBH-76-12-11-66 (less bypass) Irrigation Meters (Ford) 2” → VBH-77-12-11-77 (less bypass) 1.5” → VBH-76-12B-11-66 (13” lay length) Commercial Meters (Ford) 2” → VBH-77-12B-11-77 (15.25” lay length) ---PAGE BREAK--- Approved Meters Residential Meters (Sensus) ¾” → i-Perl Perl Electromagnetic Meter. 7.5” Lay Length with TR/PL Touch Coupler Wire. Programmed to Read in 1000 U.S. Gallons. ¾” → i-Perl Electromagnetic Meter 9.0” Lay Length with TR/PL Touch Coupler Wire. Programmed to Read in 1000 U.S. Gallons. 1” → Sensus i-Perl electromagnetic Meter 10.75” Lay Length with TR/PL Touch Coupler Wire. Programmed to Read in 1000 U.S. Gallons. Irrigation Meters (Sensus) 1.5” → Sensus OMNI T-2 Meter with 13.0 “ Lay Length. Flow Range 1.25 to 200 GPM. 2” → OMNI T-2 Meter with 17.0” Lay Length. Flow Range 1.5 to 250 GPM. 3” → OMNI T-2 Meter with 19.0” Lay Length. Flow Range 2.5 to 650 GPM. Commercial Meters (Sensus) 1.5” → OMNI C-2 Meter with 13.0” Lay Length. Flow Range 0.5 to 200 GPM. 2” → OMNI C-2 Meter with 15.125” Lay Length. Flow Range 0.5 to 200 GPM. 3” → OMNI C-2 Meter with 17.0” Lay Length. Flow Range 1.0 to 500 GPM. Restraints Fire hydrant valves shall be installed on swivel tee’s Fire hydrant runs shall be restrained with tie rods. Meg a Lugs are not allowed on PVC pipe as a permanent restraint. Tapping saddles larger than 60% of the main pipe diameter or taps on AC pipe shall fully enclose the tapped pipe. ---PAGE BREAK--- Standards and Specifications Section 300 Wastewater Facilities Page 1 Section 300 Wastewater Facilities 300. WASTEWATER FACILITIES 2 300.1. 2 300.2. ALIGNMENT AND 2 300.3. PROTECTION OF EXISTING UNDERGROUND 2 300.4. UNDERDRAIN 2 300.5. HANDLING PIPE AND 3 300.6. WASTEWATER PIPE INSTALLATION 3 300.7. BACKFILL FOR PIPELINES AND SERVICE 4 300.7.1. Backfill 5 300.7.2. Maintenance of 5 300.8. COMPACTION 5 300.9. SPECIAL 6 300.10. TAPPING THE MAIN 6 300.11. CONNECTIONS TO EXISTING 7 300.12. CONSTRUCTION OF MANHOLES AND 7 300.13. STEEL CASING AND CARRIER PIPE INSTALLATION 8 300.14. WYES AND RISERS FOR SERVICE CONNECTIONS 9 300.15. TESTING AND 9 300.16. CONNECTION TO CITY WASTEWATER SYSTEM 301. WASTEWATER LINE 301.1.1. Industrial 301.1.2. Other Requirements 302. RESTORATION AND CLEANUP DRAWINGS 300-1 Standard Manhole 300-1a Water Stop 300-1b Standard Drop Manhole 300-2 Shallow Manhole 300-3 Flow Metering and Sampling Station 300-4 Service Maintenance Line 300-5 Pipe Bedding With Underdrain ---PAGE BREAK--- Standards and Specifications Section 300 Wastewater Facilities Page 2 Section 300 Wastewater Facilities 300. Wastewater Facilities All wastewater main construction within the City system and all service line construction connecting to the City's wastewater mains will be completed in accordance with these Standards and Specifications and the accepted plans. 300.1. Installation Installation of PVC wastewater mains will conform to ASTM Designation D-2321, Recommended Practice for Underground Installation of Flexible Thermoplastic Sewer Pipe. All work will conform to the accepted plans, specifications, special provisions and the above designation, except as modified herein. 300.2. Alignment and Grade Wastewater lines shall be constructed accurately to the line and grade as shown on the accepted plans. Construction stakes will be placed by field parties under the direct supervision of a Registered Professional Engineer or a Registered Professional Land Surveyor licensed to practice in the State of Colorado. The grade and alignment will be determined by use of suitable surveying instruments (checking the invert of each piece of pipe) or laser equipment, operated continuously during the construction. As-built drawings, as described in Section 106.2.2, As-Built Drawings, of these Standards and Specifications, will be furnished to the City Engineer. 300.3. Protection of Existing Underground Utilities The Contractor will be held responsible for the protection of public improvements as stated in Section 103.1, Protection of Public and Utility Interests, of these Standards and Specifications. It will be the contractor’s responsibility to replace all public improvements so damaged at his own expense. 300.4. Underdrain Pipe Underdrains will be installed where shown on the accepted plans as required by Section 1300.9, Underdrain Pipe, of these Standards and Specifications. Underdrains will be daylighted to the nearest suitable point acceptable to the City Engineer. The trench will be excavated to the required depth and width and backfilled with underdrain bedding material. Where underdrain pipe is required, the thickness of underdrain bedding shall be increased to provide 4 inches of bedding material under the underdrain pipe and 4 inches of bedding material between the underdrain pipe and the wastewater pipe. The underdrain pipe will be installed to a true line and grade and held in place with underdrain bedding material as shown on Standard Drawing No. 300-5. Underdrain pipe shall be provided with clean-out ---PAGE BREAK--- Standards and Specifications Section 300 Wastewater Facilities Page 3 wyes within each manhole. Underdrain pipe will be continued under manholes by use of suitable bends and other fittings. 300.5. Handling Pipe and Fittings All pipe, fittings and specials will be unloaded, stockpiled, hauled, distributed, installed and otherwise handled in a manner that will prevent breakage or other damage thereto and which will insure delivery and installation in a sound and acceptable condition. 300.6. Wastewater Pipe Installation Wastewater lines will be constructed continuously upgrade from existing wastewater lines except when otherwise approved by the City. Special care will be taken to lay wastewater pipe to exact line and grade with spigot ends pointing in the direction of flow. A continuous trough will be pared or excavated in the bedding to receive the bottom quadrant of the pipe barrel. Bell holes will be excavated so that after placement, only the barrel of the pipe receives pressure from the trench bottom. The bedding material will be placed in the trench bottom, to a thickness of 4 inches to 6 inches prepared as described above, to provide a uniform and continuous bearing support for the pipe at every point between bell holes. Preparatory to making pipe joints, all surfaces of the joint will be clean and dry. Lubricants will be used as recommended by the pipe manufacturer. The pipe will be set in position and checked for line and grade using care to keep the joint absolutely free of dirt. When final grade is achieved, the joint will be carefully pushed home using approved methods of leverage. Care will be taken so that the bell end of the pipe will not be deflected to the extent that the gasket is pinched or rolled. Adjustment to final line and grade will then be made. If O-ring gaskets are used, immediately after completing the joint, the seating of the gasket will be checked around the entire circumference of the pipe by visual and finger inspection. PVC wastewater pipe will be secured in place by installation of bedding material tamped under and along it up to a level of 6 inches over the top of the pipe. The City will be notified at least two working days in advance of pipe being laid in any trench. No pipe will be covered until it has been inspected by a representative of the City. Excavation will not be permitted to advance more than 150 feet ahead of pipe laying and 200 feet in advance of the backfill operations. No trench will be left open overnight without the written permission of the City Engineer. The contractor shall provide and maintain adequate equipment to properly remove and dispose of all surface or groundwater entering the trench. Water shall be disposed of in a suitable manner without damage to adjacent property or without being a nuisance to public health and convenience. The use of any wastewater line to dispose of trench water will not be permitted. The trench shall be dry at all times during pipe installation and so maintained until the joining operation is complete. All wastewater lines will be kept thoroughly clean and free of gravel, dirt and debris. Whenever work ceases for any reason, the unfinished end of the pipe will be securely closed with a temporary tight fitting plug. ---PAGE BREAK--- Standards and Specifications Section 300 Wastewater Facilities Page 4 300.7. Backfill for Pipelines and Service Lines Suitable backfill shall be as defined in Section 1004.1 of these Standards and Specifications. In addition, all wood or other organic material and deleterious substances must be removed. Clay and similar material with a liquid limit in excess of 35 and a plasticity index in excess of 6 (determined in conformity with AASHTO T 89 and T 90) will not be considered suitable for backfilling in trenches located in improved streets, roads, highways and thoroughfares. When the excavated material is unsuitable for compaction, other material must be provided that will meet the requirements of the following table: TABLE 1000-3. BACKFILL MATERIAL FOR PIPELINES AND SERVICE LINES Sieve Size Total Percent Passing by Weight 2 inch 100 No. 4 30 – 100 No. 50 10 – 60 No. 200 5 – 20 Also, flow-fill meeting the following requirements may be used to backfill pipelines and service lines when specified in the contract. Mix: Minimum 24-hour strength: 10 psi Maximum 28-316 strength: 60 psi Maximum aggregate size: 1 inch Cement: Type I-II (Ideal ASTM C 150) Slump: 6 inch minimum, 8 inch maximum 1000-4. MIX PROPORTIONS (PER CUBIC YARD OF CONCRETE) Pounds Absolute Volume Cement (0.45 sack) 42 0.21 ft³ Water 325 (39 gallons) 5.20 ft³ 1” Aggregate (ASTM C33, Size No. 57) 1,700 10.17 ft³ Sand – ASTM C33 1,845 11.24 ft³ Air (Entrained ) 1.5% 0.41 ft³ Theoretical Unit Weight: 143.7 lbs/yd³ @ 1.5% air Theoretical Yield: 27.23 ft³ @ 1.5% air % Sand of Total Aggregate: 52% ---PAGE BREAK--- Standards and Specifications Section 300 Wastewater Facilities Page 5 Note: Aggregate weights are based on the materials being in a saturated surface-dried condition. Materials used above the subgrade level will conform to the requirements for sub-base and base course materials as defined in Section 500, City Street Construction, of these Standards and Specifications. Any bracing installed to prevent cave-ins will be withdrawn in a manner that will maintain the desired support during the backfill operations. Driven sheet pilings will be cut off at or above the top of pipe, and the portion below the cut-off line will be left in the ground. During construction, the trench backfill shall be topped out with not less than 9 inches of CDOT Class 5 or 6 aggregate base course and maintained free of chuckholes, ruts and loose rock until permanent asphalt surfacing is in place. 300.7.1. Backfill Compaction Trench backfill will be placed in loose 6 inch lifts and each lift thoroughly consolidated by tamping, vibrating, or a combination thereof, until the density is equal to 95% maximum dry density based on a site specific standard proctor, ASTM-D-698. Pipes, culverts, wastewater lines and other miscellaneous structures outside the roadway prism or sidewalk and not subject to traffic loads or heavy loads for a period of 2 years shall be backfilled in layers as described above but shall be compacted to approximately 85% of the maximum density. Consolidation shall be obtained by the use of hand tampers having a minimum weight of 20 pounds and a facial area in excess of 24 square inches. Hydrohammers shall not be used until the trench backfill has been placed and compacted to within 3 feet of the finished grade by the lift method. Large roller, tractor-drawn equipment or hydrohammers shall not be used within 18 inches of rigid pipe or 36 inches of flexible pipe. Flooding or jetting of trenches will not be permitted unless specific written approval is obtained from the City engineer. 300.7.2. Maintenance of Backfill All backfill shall at all times during construction be maintained to the satisfaction of the City Engineer. Access across trenches for driveways and streets shall be maintained free of hazards to traffic or pedestrians. 300.8. Compaction Testing The compaction of the bedding and all types of backfill shall be tested at a rate of at least one test per 200 cubic yards of fill material or portions thereof and at least one test per 250 feet, whichever controls. The testing shall be at various depths and locations. The City Engineer may require additional testing around structures, manholes, valve boxes, ---PAGE BREAK--- Standards and Specifications Section 300 Wastewater Facilities Page 6 etc. The Contractor will also have tests provided to the City for water and/or wastewater service lines as directed by the City Inspector. Initial test results shall be submitted to the City Engineer within 24 hours of the test or on the next working day. Compaction testing shall be performed by private engineering or geotechnical firms at the Contractor’s expense. Compaction testing shall be performed by a qualified technician who works under the direct supervision of a Registered Professional Engineer. Final soils compaction reports shall be prepared and signed by a Registered Professional Engineer who is registered in the State of Colorado and who is qualified to prepare such reports. Reports shall be submitted to the City Engineer within one week of the test. 300.9. Special Conditions Subsurface investigation - Prior to the connection of any planned utility line to an existing line, the Contractor shall expose the existing utility at the points of connection in order to verify the elevations and materials of construction. The City Engineer shall be notified a minimum of 2 working days before such an investigation is performed. The Contractor shall also expose utilities as they cross each other to allow for verification of elevation and materials of construction. The City Engineer will evaluate this information and provide revisions, if required, within 3 working days of the completion of the investigation. Telephone lines - Where underground telephone lines are encountered which were not shown on the accepted plans, they shall be relocated as directed by Qwest and in accordance with its specifications. The Contractor shall coordinate this work with all other phases of construction to avoid further conflicts. Gas and electric lines - Where underground gas and electric lines are encountered that were not shown on the accepted plans, they shall be relocated as directed by Xcel and in accordance with its specifications. The Contractor shall coordinate this work with all other phases of construction to avoid further conflicts. 300.10. Tapping the Main Where wyes have not been installed in the wastewater main, the main will be tapped by machine drilling a hole into it sized to fit the saddle being used for the tap. The drilling machine and method of drilling shall be approved by the City Engineer. A representative of the City shall inspect the main and saddle at every tap prior to backfilling. In the event that a tap is covered before it is inspected, the Contractor, at his own expense, shall uncover the tap and remove any concrete or mortar from around the fitting to allow for a visual inspection of the tap and the main. If the wastewater main is cracked or broken during the process of locating and tapping, the Contractor shall, at his expense, immediately repair the broken pipe. ---PAGE BREAK--- Standards and Specifications Section 300 Wastewater Facilities Page 7 300.11. Connections to Existing Manholes Wastewater pipe connections to existing manholes, where there is no pipe stubbed out, will be made in such a manner that the finished work will conform as nearly as practicable to the essential requirements specified for new manholes. The Contractor shall core a hole in the existing manhole where practical. If not, the contractor will break out as small an opening in the existing manhole as necessary to insert the new wastewater pipe. Joints shall be mechanically sealed using Link-Seal brand connector with non-metallic grout on both sides or approved alternate watertight connection. The existing concrete foundation bench will be chipped to the cross-section of the new pipe in order to form a smooth continuous invert similar to what would be formed in a new concrete base. Link-Seal brand (or approved equivalent) will be used between the pipe and the core hole with non-shrink, non-metallic grout sealing the opening on both sides of the Link-Seal. The connection will be watertight. Alternative methods may be considered at the discretion of the City Engineer. 300.12. Construction of Manholes and Clean-outs Manholes and clean-outs will be constructed in accordance with Standard Drawings No. 300-1 or No. 300-2. The main wastewater will be carried through manholes by split pipe wherever practicable. Concrete shall be 3000 psi minimum 28-day strength. Concrete foundations (bases) will extend at least 6 inches below the bottom of the pipe and will be benched up to at least 2 inches over the top of the pipe. The concrete manhole floor between the wastewater pipe and the outer portions of the bench will be flush with the top edges at the pipe spring line and will slope upward at least 2 inches per foot. Wherever grade and alignment permit, the wastewater line will be laid continuously through manhole locations and the manhole built later. In such cases, the foundation will be poured, as above and the floor of the manhole sloped upward at least 2 inches per foot out from the spring line of the pipe. When pouring the base, care must be taken to prevent flotation of the pipe. After the manhole is built, the upper half of the pipe will be broken out and the rough edges smoothed with cement grout. Where it is not practicable to use split pipe through manholes due to breaks in alignment, grade, or elevation of intersecting wastewater lines, the wastewater invert will be made of concrete deposited between forms. The shape of the invert will conform exactly to the lower half of the pipe it connects. Side branches will be constructed with as large a radius of curvature as possible. Inverts will be plastered with cement mortar and left smooth and clean. Where called for on the plans, a pipe bell will be stubbed out and plugged. The bell will be placed as close to the manhole wall as possible. Precast manhole sections will not be placed on the foundation until after it has reached sufficient strength to provide support without damage. The top of the bench will be thoroughly cleaned. Ram-Neck sealant will be applied to the precast section bearing seat. Each succeeding precast section will be jointed in a similar manner and the joints grouted for a smooth finish, in and out. All lifting holes and other imperfections in the interior manhole wall will be filled with cement mortar. ---PAGE BREAK--- Standards and Specifications Section 300 Wastewater Facilities Page 8 300.13. Steel Casing and Carrier Pipe Installation Pits shall be excavated such that the timber blocking can be installed to give an unyielding backing for the hydraulic boring machine or jacks and to prevent sloughing of the header face. Subgrade on which rails or guides are to be set shall be stabilized with washed rock where soft or springy ground is encountered. Excavation and casing installation shall be performed simultaneously. At no time shall the advancing edge of the casing trail the excavation by more that 12 inches. Sections of the steel casing shall be trimmed, beveled and aligned in the pit so that when welded together the thrust of the boring machine will be uniformly transmitted through the casing in a horizontal plane. Welds shall be made to provide a solid, firm watertight connection without the use of butt straps. The casing pipe shall be installed by boring or jacking upgrade from the outlet end. When the carrier pipe to be installed is for gravity flow, the horizontal and vertical alignments of the casing pipe, when in place, shall not vary from those called for on the accepted plans by more than the following: Alignment Entrance Midpoint Outlet Horizontal +0.02' +0.35' +0.70' Vertical +0.02' +0.10', -0.05 +0.20', -0.10 When excavation exceeds the advancing edge of the casing by more than 12 inches or sloughing of the hanging wall occurs such that voids are created along or above the casing, external grouting of the casing will be required. Grouting shall be accomplished by pumping at between 5 and 10 psi, Portland cement and mortar sand mixed with sufficient water to provide a slump of less than 2 inches through grout holes in the casing until all voids are filled. Grout holes, 1 inch to 2 inches in diameter, shall be provided or drilled in the casing on 4 foot centers along the pipe arch and at 8 foot centers along each spring line. As grouting advances each of the completed grout holes shall be plugged to a watertight condition. Each section of carrier pipe shall have two redwood skids or approved spacers attached to the pipe prior to being set in the casing. Subsequent sections shall be properly joined to each other as they are set and the assembled line gradually threaded through the casing by means of applying force at the exposed end of the carrier pipe. Care shall be exercised to provide watertight joints and to protect the ends of the pipe as they are pushed by uniformly transferring said force through the pipe in a horizontal plane. It may be necessary to vary the quadrant location and thickness of the redwood skids to obtain a uniform grade through the carrier pipe. This is especially critical on gravity lines when the alignment and grade specified for the casing pipe approaches the maximum allowable limits specified above. After threading and aligning the carrier pipe, the void between the carrier and the casing shall be filled with clean sand. Sand, under pressure, shall be blown in from each end through a 1 inch to 2 inch diameter hose and nozzle, making sure that the center portion is filled first. Once the center portion is filled, the nozzle shall be made to gradually recede, ---PAGE BREAK--- Standards and Specifications Section 300 Wastewater Facilities Page 9 while continuing blowing sand and filling the void, until the entire line is filled. Unless otherwise specified, backfill will be considered complete when all voids below the carrier pipe spring line have been filled. The top elevation of the sand should be left 1 to 2 inches above said spring line to allow for settlement. 300.14. Wyes and Risers for Service Connections The Contractor will place wyes, stubs and risers where required by the accepted plans. Wyes will be angled upwards so that the upper invert of a one-eighth bend connected to the fitting will have an elevation equal to or higher than the inside crown of the wastewater main. Riser connections will be installed where the elevation of the top of the branch is more than 12 feet below finished ground. Riser connections will ordinarily reach to a grade 10 feet below finished ground surface. Water-tight plugs will be installed in each branch pipe or stub. Wye and riser locations will be marked with a 12 gauge copper wire with yellow insulation run from the plugged end up 12 inches below the ground surface and tied off to a 24 inch piece of 2 inch by 4 inch lumber. All applicable portions of Section 300 of these Standards and Specifications shall apply. As-built measurements will be made by the Contractor or his representative to reference the wye or riser connection to the nearest manhole before backfill. Said measurements will be carefully and accurately made and recorded and will be shown on the as-built plans as required by Section 106.2.2, As-Built Drawings, of these Standards and Specifications. Service locations will be marked with a on the curb. 300.15. Testing and Inspection Prior to final acceptance, tests for water tightness will be conducted by the Contractor, at his own expense, for all new wastewater line construction. Tests shall be completed under the direction of the City Engineer. The City Engineer may require that the first two manholes, including the main between them, of all wastewater projects be tested before further construction to permit initial observation of the quality of construction workmanship. Additional testing may be required by the City Engineer during the course of construction if infiltration appears to be excessive or the quality of workmanship is questionable. Low pressure air testing of the wastewater lines (including services) and vacuum testing of all manholes will be required by the City Engineer. Air and vacuum testing shall be completed in accordance with ASTM C-828 and as described herein. The Contractor shall provide all equipment and personnel necessary to perform the required tests. The City Engineer shall record times and pressure and vacuum readings during the test period. A test section shall not be any longer than the length of pipe between adjacent manholes. The low pressure air test for wastewater lines and the vacuum test for manholes shall be done after completion of backfilling and compaction. If the City Engineer determines that reliable and uniform results are produced by the Contractor's construction methods, the low pressure air test may be done after initial backfill and compaction. a. Air Testing Procedure - The ends of the wastewater pipe being tested shall be plugged and braced and the test section shall be pressurized to 4 psi. The pressure pump shall be turned off and the air in the pipe allowed to stabilize for a minimum of two minutes. The time will be monitored as the line either holds pressure or drops ---PAGE BREAK--- Standards and Specifications Section 300 Wastewater Facilities Page 10 no more than 1 psi (if the ground water is higher than the top of the pipe, the test pressure will be increased to account for the high groundwater). The pressure must remain within the allowable limits for the time indicated by using the following formula: T = 0.0237 (D2 where T = time of test (in seconds) ) L = length of pipe being tested (in feet) D = diameter of pipe (in inches) or as indicated in the following table: Specified Test Duration for Length of Pipe Indicated (min:sec) Pipe Diameter Pipe Length (feet) 0 - 150 200 250 300 350 400 500 4" 3:46 3:46 3:46 3:46 3:46 3:46 3:46 6" 5:40 5:40 5:40 5:40 5:40 5:42 7:07 8" 7:34 7:34 7:34 7:36 8:52 10:08 12:38 10" 9:26 9:26 9:53 11:52 13:51 15:49 19:45 12" 11:20 11:24 14:15 17:05 19:56 22:47 28:26 15" 14:10 17:48 22:15 26:42 31:09 35:36 44:26 Sections of pipe which fail the air test shall have the defects repaired and the test shall be repeated. Repair and repeat testing shall be continued until the testing requirements are met. b. Vacuum Testing Manholes - Manholes shall be tested before the ring and cover and grade adjustment rings have been installed. All pipes entering the manhole shall be plugged and braced and a vacuum of 10 inches of mercury shall be drawn. The vacuum pump shall be turned off and the time monitored as the vacuum drops 1 inch. The vacuum must not drop more than 1 inch for the duration of the time indicated in the following table: Specified Test Duration for Diameter of Manhole (duration indicated in min:sec) Manhole Diameter (inches) 1:00 1:15 1:30 48 _ 60 72 Manholes which fail the vacuum test shall have the defects located and repaired and the test shall be repeated. Repair and repeat testing shall be continued until the testing requirements are met. All new wastewater liness must be jetted and video inspected prior to acceptance by the City. The City, at the Contractor's expense, shall jet-rod the wastewater lines and have the ---PAGE BREAK--- Standards and Specifications Section 300 Wastewater Facilities Page 11 lines inspected with TV video. If, after visual inspection of the wastewater main, the City Engineer suspects that there is a problem, he may require that alignment, infiltration, exfiltration and deflection tests be completed by the Contractor at the Contractor's expense. When required, infiltration tests will be conducted by placing an approved, calibrated V- notch weir in the line just above the lower manhole and plugging the line just above the upper manhole. Up to an hour time lapse will be allowed for the level of water behind the weir to stabilize before it is read. Any foreign matter hanging to the weir will be dislodged before reading. Successive readings will be taken until consistent results are attained. When required, exfiltration tests will be conducted by plugging the line just above both the upper and lower manholes and adding water to the wastewater line up to a level marked in the upper manhole to produce a 4 foot head on the invert of the line at the midpoint between manholes. The water will be allowed to stand for a minimum of 4 hours (preferably overnight) to allow absorption to take place in the walls of the manhole and pipe. Water will then be added to bring the water surface back to the mark. After a carefully timed interval, varying from 15 minutes to 60 minutes, the drop in elevation of the water surface will be recorded and converted to an exfiltration rate, or a measured amount of water will be added to bring the water level back to the mark and this amount of water converted to an exfiltration rate. The exfiltration rate of the upper manhole may be determined in the same manner by plugging the line in both sides of this manhole. This amount of exfiltration may be subtracted from the rate determined above for the first test required on the project in order to determine the actual exfiltration rate resulting from the pipe joint leakage. The practical upper limit of head applied to the lower part of the line being tested is 20 feet. Whenever the line is so steep as to require more head than this, an exfiltration test will not be attempted. The basic exfiltration leakage allowance will be increased by 10% for each 2 feet that the average actual head exceeds the basic 4 feet of head, up to a maximum of 30%. Whenever the rate of infiltration or exfiltration is found to exceed the prescribed amount, the Contractor will stop all construction. The Contractor will make appropriate repairs by methods acceptable to the City Engineer and will continue to test the conduit until it is proven satisfactory. The City will not accept any sanitary wastewater line where infiltration or exfiltration tests show leakage in the wastewater line and manholes exceeding 100 gallons per inch diameter per mile per day between adjacent manholes. Final acceptance of the wastewater line will be based on an inspection covering all items in this specification. The inspection will be done in an appropriate manner by representatives of the City Engineer and shall comply with the requirements of Section 104, Inspections, of these Standards and Specifications. The Contractor will remedy, at his own expense, any poor alignment or any other defects in workmanship or materials revealed by final inspection. Final acceptance will be based on reinspection of the wastewater line after the appropriate repairs and corrections are completed. ---PAGE BREAK--- Standards and Specifications Section 300 Wastewater Facilities Page 12 300.16. Connection to City Wastewater System Flow of any kind into the existing wastewater system will not be allowed until the wastewater line has been satisfactorily completed and accepted for use by the City Engineer. 301. Wastewater Line 301.1.1. Industrial All buildings (warehouses, etc.) constructed as a shell, with the intention of only being used for subdivided suites for commercial purposes, shall be required to install service connections extending a minimum of 6 feet outside of the building with a clean-out for each set of proposed bathrooms or suites. All commercial and industrial facilities must have a double sweep clean-out on the outside of the building, located a minimum of 3 feet from the building, on the service connection. 301.1.2. Other Requirements Rainwater leaders, roof drains, surface drains or ground water drains shall not be connected to the wastewater system. Each wastewater service system shall be separate from the drainage system. Grease and sand traps will be installed where required by these Standards and Specifications and Lafayette Municipal Code, Section 95-74 (14), Oil and Grease Interceptor Installation. 302. Restoration and Cleanup Restoration and cleanup shall be completed in accordance with Section 1005, Restoration and Cleanup, of these Standards and Specifications. ---PAGE BREAK--- Standards and Specifications Section 400 Storm Drainage Facilities Page 1 Section 400 Storm Drainage Facilities Rev. 8-17-12 400. STORM DRAINAGE FACILITIES 2 400.1. GENERAL 2 400.1.1. Accepted 2 400.1.2. Permits Required 2 400.1.3. Maintenance of 2 400.2. EROSION CONTROL 2 400.2.1. General 2 400.2.2. Requirements 3 400.2.3. 3 400.2.4. Erosion Control . 3 400.2.5. Erosion Control 3 400.3. STORM DRAINAGE 3 400.3.1. 3 400.3.2. Riprap 6 400.4. 7 400.4.1. Site work and Earthwork 7 400.4.2. Alignment and 8 400.4.3. Protection of Existing Underground 8 400.4.4. Handling Pipe and 8 400.4.5. Stormwater Pipe Installation 8 400.4.6. Pipe Joints 9 400.4.7. Riprap and Filter Cloth 9 400.4.8. Backfill Compaction 400.4.9. Maintenance of Backfill 400.5. COMPACTION TESTING 400.6. SPECIAL CONDITIONS 400.7. INSPECTIONS DRAWINGS 400-1 Shallow Manhole 400-2 Stormwater Pipe Bedding 400-3 Curb Inlets Type R 400-4 Sidewalk Drainage Pipe Detail 400-6 Storm Sewer Outlet 400-7 Curb Inlet Gravel Filter 400-8 Silt Fence Erosion Barrier 400-9 Straw Bale Erosion Barrier 400-10 VTC – Rock 400-11 VTC – Cattleguard 400-12 Roof Drain to Street 400-13 Erosion Control Barriers – Residential ---PAGE BREAK--- Standards and Specifications Section 400 Storm Drainage Facilities Page 2 Section 400 Storm Drainage Facilities 400. Storm Drainage Facilities 400.1. General Provisions All storm drainage construction in the City rights-of-way will be accomplished in accordance with these Standards and Specifications, and these standards will cover not only new storm drainage construction but also repairs and maintenance of the existing facilities within the City. 400.1.1. Accepted Plans All storm drainage construction will be done in accordance with engineered construction plans for the work, prepared under the direction of a Registered Professional Engineer licensed to practice in Colorado. Plans will conform to the City's Design Criteria and must be accepted by the City Engineer. Storm drainage plans will include an Area Grading Plan and an Erosion Control plan as defined in Section 105.1, Construction Plan Requirements, of these Standards and Specifications. Where work is to be done on an irrigation ditch, the written approval of the ditch owner is required prior to approval by the City Engineer. 400.1.2. Permits Required Open channel work or other construction which will disturb more than one acre will require a Grading and Erosion Control Permit from Lafayette as well as a NPDES Permit from the State of Colorado. Work which will be part of a subdivision or redevelopment plan will not need an additional utility permit. Other work will be subject to standard right-of-way permit requirements. 400.1.3. Maintenance of Traffic Maintenance of traffic shall comply with Section 200.3, Maintenance of Traffic, of these Standards and Specifications. 400.2. Erosion Control 400.2.1. General Erosion and sedimentation are natural processes, the intensity of which is increased by land- disturbing activities that reduce or destroy the aesthetic and practical values of neighboring properties, streams and lakes. The purpose of these erosion criteria is to reduce intensified erosion, caused by either wind or water, to an acceptable level without placing undue burdens on the landowner, builder or community. ---PAGE BREAK--- Standards and Specifications Section 400 Storm Drainage Facilities Page 3 400.2.2. Requirements Erosion control measures shall be designed in conformance with Volume 3 of the UDFCD Urban Storm Drainage Criteria Manual. All land-disturbing activities within the City of Lafayette shall be in compliance with applicable Colorado Discharge Permit System (CDPS) Stormwater, Colorado Air Quality Control Commission regulations, and the NPDES Phase II storm water regulations. 400.2.3. Submittal 400.2.4. Erosion Control Measures A discussion summarizing erosion control methods will be submitted as part of the preliminary and final drainage reports as required in Section 105.2, Engineering Reports, of these Standards and Specifications. A detailed erosion control plan must accompany the Area Grading Plan and approved Drainage Plan as required in Section 105.1.8, Erosion Control Plan Details, of these Standards and Specifications. The erosion control plan must be submitted to, and approved by, the City of Lafayette Public Works Department prior to receiving a grading and erosion control permit. Detailed erosion control measures must be provided to protect the following: 1. Inlets and culverts 2. Drainageways having channel flow lines which exceed 1% slope 3. Streams or other water bodies which are immediately adjacent to land disturbed by construction activity 4. Cut and fill areas where exposed soil exists 5. Properties and improved streets adjacent to construction activity 6. Other as required by the City Engineer Temporary erosion control measures such as sediment traps, hay bales or silt fences must be properly placed in accordance with the approved grading plan prior to any earthmoving on site. Erosion control measures shall be kept in good repair and fully functional until the erosion potential from the site no longer exists. Permanent erosion control (sod, seed, mulching, etc.) will be in place prior to the request for a Certificate of Occupancy. 400.2.5. Erosion Control Structures Standard details and specifications are provided in Standard Drawings 400-7 to 400-13. When applicable, details of additional erosion control measures should be obtained from the UDFCD Urban Drainage Criteria Manual, Volume 3. 400.3. Storm Drainage Construction 400.3.1. Materials 400.3.1.1. Pipe Reinforced concrete pipe (RCP) shall be manufactured in accordance with ASTM C-76. All applicable portions of Section 706, Concrete and Clay Pipe, of the CDOT Standard Specifications for Road and Bridge Design shall apply. ---PAGE BREAK--- Standards and Specifications Section 400 Storm Drainage Facilities Page 4 Corrugated aluminum or steel pipe (CMP) shall be fabricated in accordance with all applicable portions of Section 707, Metal Pipe, of the CDOT Standard Specifications for Road and Bridge Design. Special permission is required to install CMP in public rights-of- way. Plastic storm drainage pipes are not allowed within Lafayette right-of-way. 400.3.1.2. Manholes and Inlets Manholes and inlets may be constructed of cast-in-place or precast concrete. Manhole materials shall comply with all applicable portions of Section 1300.10.4, Manholes, of these Standards and Specifications. Inlets shall conform to applicable Colorado Department of Highways Standards. Residential inlets shall be CDOT Type 400.3.1.3. Concrete Concrete will conform to Section 600, Concrete, of these Standards and Specifications, for Portland cement concrete work. Type II cement will be used. Concrete encasement of pipe will conform to the details shown on the accepted plans. 400.3.1.4. Cast Iron Fittings All cast iron manhole rings and covers, and other iron castings will be made of tough gray pig iron conforming to ASTM Designation A-48 and will be free from cracks, holes, swells, and cold shuts, and will have a smooth workman-like finish. All covers will be purchased from the City of Lafayette and will be East Jordan Manhole Covers product number 00240846. Cast iron manhole rings will be of the NEENAH model R-1683 (or approved equal). The combined weight of the castings will not be less than 400 pounds. All metal bearing surfaces between the rings and cover will be machined or fabricated to insure good seating. 400.3.1.5. Bedding Material All applicable portions of Section 1004.1, Bedding Materials, of these Standards and Specifications, shall apply. 400.3.1.6. Backfill for Pipelines Suitable backfill shall be as defined in Section 1004.1 of these Standards and Specifications. In addition, all wood or other organic material and deleterious substances must be removed. Clay and similar material with a liquid limit in excess of 35 and a plasticity index in excess of 6 (determined in conformity with AASHTO T 89 and T 90) will not be considered suitable for backfilling in trenches located in improved streets, roads, highways and thoroughfares. When the excavated material is unsuitable for compaction, other material must be provided that will meet the requirements of the following table: ---PAGE BREAK--- Standards and Specifications Section 400 Storm Drainage Facilities Page 5 TABLE 1000-3. BACKFILL MATERIAL FOR PIPELINES AND SERVICE LINES Sieve Size Total Percent Passing by Weight 2 inch 100 No. 4 30 – 100 No. 50 10 – 60 No. 200 5 - 20 Also, flow-fill meeting the following requirements may be used to backfill pipelines and service lines when specified in the contract. Mix: Minimum 24-hour strength: 10 psi Maximum 28-316 strength: 60 psi Maximum aggregate size: 1 inch Cement: Type I-II (Ideal ASTM C 150) Slump: 6 inch minimum, 8 inch maximum 1000-4. MIX PROPORTIONS (PER CUBIC YARD OF CONCRETE) Pounds Absolute Volume Cement (0.45 sack) 42 0.21 ft³ Water 325 (39 gallons) 5.20 ft³ 1” Aggregate (ASTM C33, Size No. 57) 1,700 10.17 ft³ Sand – ASTM C33 1,845 11.24 ft³ Air (Entrained ) 1.5% 0.41 ft³ Theoretical Unit Weight: 143.7 lbs/yd³ @ 1.5% air Theoretical Yield: 27.23 ft³ @ 1.5% air % Sand of Total Aggregate: 52% Note: Aggregate weights are based on the materials being in a saturated surface-dried condition. Materials used above the subgrade level will conform to the requirements for sub-base and base course materials as defined in Section 500, City Street Construction, of these Standards and Specifications. Any bracing installed to prevent cave-ins will be withdrawn in a manner that will maintain the desired support during the backfill operations. Driven sheet pilings will be ---PAGE BREAK--- Standards and Specifications Section 400 Storm Drainage Facilities Page 6 cut off at or above the top of pipe, and the portion below the cut-off line will be left in the ground. During construction, the trench backfill shall be topped out with not less than 9 inches of CDOT Class 5 or 6 aggregate base course and maintained free of chuckholes, ruts and loose rock until permanent asphalt surfacing is in place. Permanent bottom lifts of asphalt pavement will be in place by Friday night for continuing construction projects. 400.3.2. Riprap Rock used for riprap shall be hard, durable, angular in shape and free from cracks, overburden, shale and organic matter. Neither breadth nor thickness of single stone shall be less than one-third its length and rounded stone will not be accepted. The rock shall sustain abrasion test (Los Angeles machine - ASTM C0535-69) and shall sustain a loss of not more than 10% after 12 cycles of freezing and thawing (AASHTO test 103 for ledge rock procedure The rock shall have a minimum specific gravity of 2.50. Classification and gradation for riprap are shown in Table 400-1. The riprap designation and total thickness of riprap shall be as shown on the accepted plans. The maximum stone size shall not be larger than the thickness of the riprap. TABLE 400-1 CLASSIFICATION AND GRADATION OF RIPRAP Riprap Designation % Smaller Than Given Size By Weight Intermediate Rock Dimension (Inches) d(50)* (Inches) Type VL 70-100 12 50-70 9 35-50 6 2-10 2 Type L 70-100 15 50-70 12 35-50 9 2-10 3 Type M 70-100 21 50-70 18 35-50 12 12 2-10 4 Type H 70-100 30 50-70 24 35-50 18 18 2-10 6 Type VH 70-100 42 50-70 33 35-50 24 24 ---PAGE BREAK--- Standards and Specifications Section 400 Storm Drainage Facilities Page 7 Riprap Designation % Smaller Than Given Size By Weight Intermediate Rock Dimension (Inches) d(50)* (Inches) 2-10 9 *d(50) = Mean particle size Bury Types VL and L with native top soil and re-vegetate to protect from vandalism. 400.3.2.1. Filter Cloth Filter cloth shall be manufactured especially for the stability of erosion control construction and made from polyethylene, polypropylene or polyester yarns in accordance with the following: a. Weight 4.0 oz/yd ASTM D1910 b. Thickness 15 mils ASTM D1777 c. Grab Strength 110 lbs ASTM D1682 d. Elongation Break 50% ASTM D1682 e. Mullen Burst Strength 125 psi ASTM D3786 f. Puncture Strength 40 lb ASTM D751 g. Trapezoid Tear Strength 40 lb ASTM D751 h. Equivalent Opening Size 70-100 U.S. Sieve CW 02215 400.3.2.2. Filter Material The filter material, which shall be placed on top of the filter cloth (at specified thickness) prior to placement of the riprap, shall meet the requirements of "Stabilization Material" as defined in Section 1004.1, Definitions, of these Standards and Specifications. When requested by the City Engineer, the Contractor shall furnish copies of tests from a certified and acceptable testing laboratory for the following: a. Gradation and soundness of riprap b. Gradation of filter material c. Strength and characteristic tests for filter cloth 400.4. Installation Installation of RCP Storm water pipes will conform to the CONCRETE PIPE INSTALLATION MANUAL, American Concrete Pipe Association. All work will conform to the accepted plans, specifications, special provisions and the above designation, except as modified herein. 400.4.1. Site work and Earthwork Site work and earthwork shall be performed in accordance with Section 1000.00, Site Work and Earthwork, of these Standards and Specifications. ---PAGE BREAK--- Standards and Specifications Section 400 Storm Drainage Facilities Page 8 400.4.2. Alignment and Grade Stormwater lines and structures appurtenant thereto shall be constructed accurately to the line and grade as shown on the accepted plans. Construction stakes will be placed by field parties under the direct supervision of a Registered Professional Engineer or a Registered Professional Land Surveyor licensed to practice in the State of Colorado. The grade and alignment will be determined by use of suitable surveying instruments (checking the invert of each piece of pipe) or laser equipment, operated continuously during the construction. As-built drawings, as described in Section 106.2.2, Construction Plan Requirements, of these Standards and Specifications, will be furnished to the City Engineer. 400.4.3. Protection of Existing Underground Utilities The Contractor will be held responsible for the protection of public improvements as stated in Section 103.1, Protection of Public and Utility Interests, of these Standards and Specifications. It will be the contractor’s responsibility to replace all public improvements so damaged at his own expense. 400.4.4. Handling Pipe and Fittings All pipe, fittings and specials will be unloaded, stockpiled, hauled, distributed, installed and otherwise handled in a manner that will prevent breakage or other damage thereto and which will insure delivery and installation in a sound and acceptable condition. 400.4.5. Stormwater Pipe Installation Stormwater lines will be constructed continuously upgrade from an existing outfall except when otherwise approved by the City. Special care will be taken to lay pipe to exact line and grade with spigot ends pointing in the direction of flow. A continuous trough will be pared or excavated in the bedding to receive the bottom quadrant of the pipe barrel. Bell holes will be excavated so that after placement, only the barrel of the pipe receives pressure from the trench bottom. The bedding material will be placed in the trench bottom, to a thickness of 4 inches to 6 inches prepared as described above, to provide a uniform and continuous bearing support for the pipe at every point between bell holes. Preparatory to making pipe joints, all surfaces of the joint will be clean and dry. Lubricants will be used as recommended by the pipe manufacturer. The pipe will be set in position and checked for line and grade using care to keep the joint absolutely free of dirt. When final grade is achieved, the joint will be carefully pushed home using approved methods of leverage. Care will be taken so that the bell end of the pipe will not be deflected to the extent that the gasket is pinched or rolled. Adjustment to final line and grade will then be made. If O-ring gaskets are used, immediately after completing the joint, the seating of the gasket will be checked around the entire circumference of the pipe by visual and finger inspection. PVC pipe will be secured in place by installation of bedding material tamped under and along it up to a level of 6 inches over the top of the pipe. ---PAGE BREAK--- Standards and Specifications Section 400 Storm Drainage Facilities Page 9 The City will be notified at least two working days (48 hours) in advance of pipe being laid in any trench. No pipe will be covered until it has been inspected by a representative of the City. Excavation will not be permitted to advance more than 150 feet ahead of pipe laying and 200 feet in advance of the backfill operations. No trench will be left open overnight without the written permission of the City Engineer. The contractor shall provide and maintain adequate equipment to properly remove and dispose of all surface or groundwater entering the trench. Water shall be disposed of in a suitable manner without damage to adjacent property or without being a nuisance to public health and convenience. The use of any stormwater lines to dispose of trench water will not be permitted. The trench shall be dry at all times during pipe installation and so maintained until the joining operation is complete. 400.4.6. Pipe Joints Pipe joints will be constructed as designated on the approved construction plans or as otherwise approved by the City Engineer. Rubber gasket joints for concrete pipe will conform to ASTM C-443. Corrugated metal pipe joints will be installed according to the pipe manufacturer's recommendations. Cement mortar joints will be constructed with mortar mixture composed of one part Portland cement to three parts sand and enough water to produce a workable mix. Mortar that has started to set will be discarded and a new batch prepared. 400.4.7. Riprap and Filter Cloth Excavation for riprap shall conform to all applicable portions of Section 1000, Site Work and Earthwork, of these Standards and Specifications. The Contractor shall complete the excavation in accordance with the accepted plans or as directed by the City Engineer; then he shall place the filter cloth over the graded areas loosely enough so that any protrusions from underneath or applied bends to the cloth will not cause stretching of the cloth beyond elastic limits. The outer edge of the filter cloth shall be folded vertically upward at the trench. All overlapping joints shall be a minimum of 2 feet wide, with the upstream section overlapping the portion. The overlapping joints shall be secured with staples at each edge of the adjoining sections of cloth, and spaced at 2 foot intervals. Any holes, rips or other damage to the filter cloth shall be repaired by the Contractor, at his expense, in accordance with the manufacturer's recommendations. Stabilization material, as described in Section 1004.1, Definitions, of these Standards and Specifications, shall be placed on top of the filter cloth (where filter cloth is used) to a thickness of 6 inches. The material shall be placed using equipment which will not rip, tear or otherwise damage the filter cloth. Any damaged areas shall be repaired at the Contractor's expense. The material shall be screeded to give a finished surface which is within 1 inch of the specified thickness. ---PAGE BREAK--- Standards and Specifications Section 400 Storm Drainage Facilities Page 10 Riprap shall be placed to conform to the details shown on the accepted plans. The larger size stones shall be placed first and roughly arranged in close contact. The toe trench and foundation course shall be closed first. The spaces between the larger stones shall then be filled with smaller stone of suitable size, so placed as to leave the surface evenly stepped, conforming to the contour required. The finished surface shall be even and tight and shall not vary from the planned surface by more than one quarter foot per foot of depth. The material may be machine placed with sufficient hand work to accomplish the requirements noted herein. Where riprap is to be grouted, the stones shall be laid with care to prevent earth and sand from filling the joints. Joints shall be filled with grout and the surfaces swept with a stiff broom. The work shall be protected and kept moist during hot weather for at least three days after grouting, or coated with a clear membrane curing compound. Grout shall consist of one part cement and three parts aggregate, by volume. The Portland Cement shall be Type II and aggregate shall be two parts sand and one part gravel passing a ⅜ inch square mesh screen. The amount of water in the mix shall be such as to permit gravity flow into the interstices with limited spading and brooming. Except when approved in writing by the City Engineer, the Contractor shall cease all grouting or placement of concrete into which riprap is to be placed when the descending air temperature in the shade and away from artificial heat falls below 35 degrees Fahrenheit and there is frost in the subgrade. When concreting is permitted during cold weather, the temperature of the mix shall not be less than 60 degrees Fahrenheit at the time of placing. The Contractor shall not place filter cloth, stabilization material, or riprap on frozen ground. 400.4.8. Backfill Compaction Trench backfill will be placed in loose 6 inch lifts and each lift thoroughly consolidated by tamping, vibrating, or a combination thereof, until the density is equal to 95% maximum dry density based on a site specific standard proctor, ASTM-D-698. Pipes, culverts, wastewater lines and other miscellaneous structures outside the roadway prism or sidewalk and not subject to traffic loads or heavy loads for a period of 2 years shall be backfilled in layers as described above but shall be compacted to approximately 85% of the maximum density. Consolidation shall be obtained by the use of hand tampers having a minimum weight of 20 pounds and a facial area in excess of 24 square inches. Hydrohammers shall not be used until the trench backfill has been placed and compacted to within 3 feet of the finished grade by the lift method. Large roller, tractor-drawn equipment or hydrohammers shall not be used within 18 inches of rigid pipe or 36 inches of flexible pipe. Flooding or jetting of trenches will not be permitted unless specific written approval is obtained from the City engineer. ---PAGE BREAK--- Standards and Specifications Section 400 Storm Drainage Facilities Page 11 400.4.9. Maintenance of Backfill All backfill shall at all times during construction be maintained to the satisfaction of the City Engineer. Access across trenches for driveways and streets shall be maintained free of hazards to traffic or pedestrians. 400.5. Compaction Testing The compaction of the bedding and all types of backfill shall be tested at a rate of at least one test per 200 cubic yards of fill material or portions thereof and at least one test per 250 feet, whichever controls. The testing shall be at various depths and locations. The City Engineer may require additional testing around structures, manholes, valve boxes, etc. The Contractor will also have tests provided to the City for water and/or wastewater service lines as directed by the City Inspector. Initial test results shall be submitted to the City Engineer within 24 hours of the test or on the next working day. Compaction testing shall be performed by private engineering or geotechnical firms at the Contractor’s expense. Compaction testing shall be performed by a qualified technician who works under the direct supervision of a Registered Professional Engineer. Final soils compaction reports shall be prepared and signed by a Registered Professional Engineer who is registered in the State of Colorado and who is qualified to prepare such reports. Reports shall be submitted to the City Engineer within one week of the test. 400.6. Special Conditions Subsurface investigation - Prior to the connection of any planned utility line to an existing line, the Contractor shall expose the existing utility at the points of connection in order to verify the elevations and materials of construction. The City Engineer shall be notified a minimum of 2 working days before such an investigation is performed. The Contractor shall also expose utilities as they cross each other to allow for verification of elevation and materials of construction. The City Engineer will evaluate this information and provide revisions, if required, within 3 working days of the completion of the investigation. Telephone lines - Where underground telephone lines are encountered which were not shown on the accepted plans, they shall be relocated as directed by Qwest and in accordance with its specifications. The Contractor shall coordinate this work with all other phases of construction to avoid further conflicts. Gas and electric lines - Where underground gas and electric lines are encountered that were not shown on the accepted plans, they shall be relocated as directed by Xcel and in accordance with its specifications. The Contractor shall coordinate this work with all other phases of construction to avoid further conflicts. When required, sidewalk drainage pipe will be constructed as detailed on Standard Drawing No. 400-4. ---PAGE BREAK--- Standards and Specifications Section 400 Storm Drainage Facilities Page 12 400.7. Inspections Refer to Section 104, Inspections, of these Standards and Specifications. ---PAGE BREAK--- Standards and Specifications Section 500 Street Construction Page 1 Section 500 City Street Construction SECTION 3 CITY STREET 3 500. CITY STREET 3 500.1. 3 500.2. CITY CAPITAL IMPROVEMENT 3 500.3. STREET ACCEPTANCE AND WARRANTY 3 500.4. TRAFFIC CONTROL 3 501. SITE WORK AND EARTHWORK (SEE ALSO SECTION 3 501.1. SUBGRADE 3 501.1.1. Subexcavation for Expansive Soils 4 501.1.2. Lime-Treated Subgrade 4 501.2. SUBGRADE 4 501.2.1. 4 502. BITUMINOUS CONSTRUCTION 4 502.1. . 4 502.2. BASE 5 502.3. HOT BITUMINOUS . 5 502.3.1. Weather 6 502.4. TACK 7 502.5. SEAL 7 502.6. REJUVENATING AGENT 7 502.7. HEATING AND SCARIFYING 7 502.8. ROTOMILLING 7 503. CONCRETE PAVEMENT 8 503.1. PORTLAND CEMENT-TREATED 8 504. APPURTENANT CONCRETE STRUCTURES 9 504.1. GENERAL 9 504.1.1. Curbs and 9 504.1.2. Sidewalks 9 504.1.3. Crosspans and Curb Return Fillets 9 504.1.4. Curb Cuts and 9 504.1.5. Curb Ramps 9 504.2. CONSTRUCTION REQUIREMENTS 9 504.2.1. Staking and Grade 9 504.2.2. Excavation and Embankment 505. INSPECTION 505.1. REQUIRED INSPECTIONS 505.2. REQUIRED TESTING 505.3. UTILITY INSTALLATIONS 505.4. STREET LIGHTING 506. STREET LANDSCAPING ---PAGE BREAK--- Standards and Specifications Section 500 Street Construction Page 2 Drawings 500-1 Major Utility Trench Patch 500-2 Pavement Replacement (Small Patch) ---PAGE BREAK--- Standards and Specifications Section 500 Street Construction Page 3 Section 500 City Street Construction 500. City Street Construction 500.1. Applicability This section contains construction testing criteria that must be met on all newly constructed streets in the City. 500.2. City Capital Improvement Projects It is recognized that the requirements contained in these Standards and Specifications are not necessarily sufficient for plans, specifications and contract administration purposes for City-administered street capital improvement projects. City contract documents govern the procedures necessary for bidding, award and construction administration for such projects. Said additional requirements and procedures may be more stringent than these Standards and Specifications. 500.3. Street Acceptance and Warranty Street sections will be accepted by the City according to Section 106, Acceptance Procedures, of these Standards and Specifications. The warranty period shall be in accordance with Section 26-19-18 of the City code and the applicable development agreement. Repairs and replacement shall be performed according to Section 106 of these Standards and Specifications. Pavement shall not exhibit any distress including, but not limited to, alligator cracking, block cracking, edge cracking, potholes, trench settlement, raveling, patching or ponding at the completion of the warranty period. Workmanship shall meet City standards. This will include thickness, crowns, drainage, areas around manholes and service covers, trench settlement, and edges against curb or drain pans. 500.4. Traffic Control Plan Prior to the commencement of any construction within the City right-of-way, the Contractor must prepare and submit for review and approval a Traffic Control Plan in conformance with Section 103.1.8, Traffic Control, Barricades and Warning Signs, of these Standards and Specifications. 501. Site Work and Earthwork (See also Section 1000) 501.1. Subgrade The bottom of the excavation for the pavement, or top of the fill, will be known as the pavement subgrade and will conform to the lines, grades and cross sections shown on the accepted plans. ---PAGE BREAK--- Standards and Specifications Section 500 Street Construction Page 4 Prior to the street being excavated, all service cuts will be checked to see if the backfill meets density requirements. If deficient, they will be recompacted and brought up to 95% maximum dry density as determined by a standard proctor, ASTM D-698. After excavation and embankment is completed and the subgrade brought to final grade, it will be rolled with compaction equipment as required to bring the subgrade to 95% of maximum dry density determined by a standard proctor, ASTM D-698. The moisture content will be within 2% of optimum. No paving, subgrade or base will be placed on soft, spongy, frozen or unstable subgrade which is considered unsuitable by the City Engineer. Proof rolling with a single-axle water truck will be required for all subgrade work. Soft and yielding material and portions of the subgrade which show deflection will be scarified and re-rolled or will be removed and replaced with subgrade material, then compacted as specified herein. Subgrade will not be approved for base course construction until it is uniformly stable and unyielding. 501.1.1. Subexcavation for Expansive Soils Subexcavation may be required depending on the soils analysis and pavement design. Special standards will be applied for expansive soils. 501.1.2. Lime-Treated Subgrade When necessary, lime treated subgrade shall conform to Section 307, Lime Treated Subgrade, of the CDOT Standard Specifications for Road and Bridge Construction. Stabilized subgrade shall extend to the back of the sidewalk for streets with attached sidewalks. Stabilized subgrade shall extend to the back of the curb for streets with detached sidewalks. Alternative methods of soil stabilization may be allowed with approval of the City Engineer. 501.2. Subgrade Construction 501.2.1. Materials Unsuitable materials will be removed and replaced with materials corresponding to the pavement design assumptions published for that street or subdivision. 502. Bituminous Construction 502.1. General The intent of this section is to specify materials and methods to be used for the construction, overlaying, seal coating and pavement rejuvenation of streets, parking lots, walks, drainways and other miscellaneous work requiring the use of aggregates. The work covered will include general requirements that are applicable to aggregate base course, bituminous base and pavements of the plant mix type, bituminous prime coat, bituminous tack coat, rejuvenating applications and asphalt concrete overlay. All workmanship and material will ---PAGE BREAK--- Standards and Specifications Section 500 Street Construction Page 5 be in accordance with requirements of these Standards and Specifications and in conformity with the lines, grades, depths, quantity requirements and the typical cross section shown on the plans or as directed by the City Engineer. 502.2. Base Course When required by the drawings, this item will consist of a foundation course composed of gravel or crushed stone and filler, constructed on the prepared subgrade. Materials and construction will be in accordance with the requirements of Section 304 of the CDOT Standard Specifications for Road and Bridge Construction. Gradation will be Class 5 (1½ inch maximum) or Class 6 (¾ inch maximum). The base course material will be placed on the previously prepared subgrade at the locations and in the proper quantities to conform to the typical cross sections as shown on the accepted plans and as directed by the City Engineer. Placing and spreading will be done by means of a spreader machine, moving vehicle, motor grader or by other approved equipment methods. The material will be placed without segregation. Any segregated areas will be removed and replaced with uniformly graded material at the Contractor's expense. The base material may be placed in lifts of up to 6 inches, providing that after compaction, uniform density is obtained throughout the entire depth of the lift. If the required depth exceeds 6 inches, it will be placed in two or more lifts of approximately equal thickness. If uniform density cannot be obtained by 6 inch lifts, the lift thickness will be reduced until a uniform minimum density is obtained. Base material will not be placed on a foundation that is soft or spongy or one that is covered by ice or snow. Base material will not be placed on a dry or dusty foundation where the existing condition would cause rapid dissipation of moisture from the base material and hinder or preclude its proper compaction. Such dry foundations will have water applied to them and will be reworked or recompacted. Rolling will be continuous until the base material has been compacted thoroughly in accordance with Section 304 of the CDOT Standard Specifications for Road and Bridge Construction. Water will be uniformly applied as needed during compaction to obtain optimum moisture content and to aid in consolidation. The surface of each layer will be maintained during the compaction operations in such a manner that a uniform texture is produced and the aggregates are firmly placed. The finished base course surface will be smooth and free of ruts and irregularities and will be true to grade and crown as shown on the plans or as directed by the City Engineer. The base course will be maintained in this condition by watering, drying, rolling or blading or as the City Engineer may direct until the surfacing is placed. 502.3. Hot Bituminous Pavement All pavement will be hot bituminous pavement of the plant mix type unless otherwise approved in writing by the City Engineer. Materials and construction will be in accordance ---PAGE BREAK--- Standards and Specifications Section 500 Street Construction Page 6 with Section 403 of the CDOT Standard Specifications for Road and Bridge Construction and the following requirements: a. All mixes shall be designed using a Super pave compactor to N design of 75 gyrations and shall include a PG 64-22 binder. b. The gradation of the mineral aggregate will be grading SX (½ inch nominal) for new street construction. Grading S (1 inch nominal) may be used for bottom lifts or in special cases as required on the accepted plans or authorized in writing by the City Engineer. Grading SG (1 inch nominal) may be used for 3½ inch or thicker bottom lifts. c. All mixes shall be designed with 1% lime. d. A maximum of 20% Reclaimed Asphalt Pavement (RAP) will be allowed in (non- polymer or non-rubberized) mixes, provided that all the requirements for hot bituminous pavement are met. e. A copy of the mix formula will be submitted to the City Engineer for review and approval at least seven days prior to starting paving work. All testing done throughout this construction period that is necessary to assure conformance of materials and workmanship to the specifications will be at the Contractor's expense. One copy of all test reports will be submitted directly to the City Engineer. In the event that a current job mix formula is not available for the materials proposed for use, the Contractor will submit a job mix formula prepared by a recognized testing laboratory for review and acceptance by the City Engineer. A report giving the properties of the materials and certifying their conformance to or deviations from the requirements of the specifications will accompany the job mix formula. 502.3.1. Weather Limitations Bituminous plant mix shall be placed only on properly constructed and accepted layers that are free from water, snow or ice. The bituminous mixtures shall be placed only when weather conditions permit the pavement to be properly placed and finished as determined by the City Engineer. The bituminous mixtures shall be placed in accordance with the following temperature limitations: Table 500-4 Minimum Air and Surface Temperatures Compacted Layer Thickness (Inches) Minimum Air and Surface Temp. (Degrees F and rising) Top Layer Other Layers 1 or less 60 50 >1 to 3 50 40 >3 30 Air temperature is taken in the shade. Surface is defined as the existing base on which the new pavement is to be placed. ---PAGE BREAK--- Standards and Specifications Section 500 Street Construction Page 7 Under certain circumstances, the City Engineer may waive minimum temperature requirements for placing prime coats and layers of bituminous mixtures below the top layer of the completed pavement. 502.4. Tack Coat When tack coat is specified on the accepted plans or required by the City Engineer, all materials and construction will be in accordance with the requirements of Section 407 of the CDOT Standard Specifications for Road and Bridge Construction. Bituminous material will be SS-1 emulsion, diluted by mixing one gallon of SS-1 emulsion with one gallon of clean water, applied at the rate of 0.05 to 0.15 gallons per square yard. 502.5. Seal Coat When seal coat is required, all materials and construction will be in accordance with the requirements of Section 409 of the CDOT Standard Specifications for Road and Bridge Construction. The type of bituminous material, cover aggregate and rates of application will be as shown on the accepted plans. 502.6. Rejuvenating Agent When a rejuvenating agent is specified on the accepted plans or required by the City Engineer, all materials and construction will be in accordance with the requirements of Section 407 of the CDOT Standard Specifications for Road and Bridge Construction. 502.7. Heating and Scarifying When heating and scarifying treatment is specified on the accepted plans or required by the City Engineer, all materials and construction will be in accordance with requirements of Section 405 of the CDOT Standard Specifications for Road and Bridge Construction. 502.8. Rotomilling Rotomilling will consist of milling, grinding or cold planing the existing pavement surface to establish a new surface profile and cross section in preparation for a bituminous overlay. After rotomilling, the surface will have a grooved or ridged finish, uniform and resistant to raveling or traffic displacement. This textured surface will have grooves of ¼ inch ± ⅛ inch. The existing surface to be ground will include bituminous pavement, concrete utility patches and a very small amount of concrete pavement. Wedge cut rotomilling will consist of rotomilling the existing pavement surface a minimum of 4 feet wide at the existing concrete gutter. The edge of the gutter end of the finished wedge cut will be 1½ inches below the edge of the existing concrete gutter. The centerline of street edge of the wedge cut will be cut ⅛ inch. The depth of cut will be determined by measuring to the top of the ridges by placing a 5 foot straight edge perpendicular to the grooving pattern. Full width rotomilling will consist of rotomilling the existing pavement surface from edge of gutter to edge of gutter to a minimum depth of 2 inches unless otherwise specified in the contract or directed by the City Engineer. ---PAGE BREAK--- Standards and Specifications Section 500 Street Construction Page 8 Rotomilling around utility castings to the depth of cut before and after encountering the castings will be included in the area of the pavement surface ground. The Contractor may choose to remove the entire existing bituminous pavement around the castings where rotomilling is not completed and replace it with bituminous surface course placed and compacted in 3 inch lifts. The Contractor will vertically cut the limits of the area to be patched, mechanically compact the existing base course and prime the bottom and vertical edges before backfilling. The Contractor will remove the cuttings immediately behind the rotomilling machine by belt loader, end loader, power sweeper and/or by hand. The removed material will be disposed of as approved by the City Engineer. The rotomilling machine will be a power operated, self-propelled machine, having a cutting drum with lacing patterns that will attain a grooved surface and produce grinding chips of less than 1 inch in size. The rotomilling machine will be equipped with a pressurized watering system for dust control. The equipment will be a type that has successfully performed similar work. The cleaning equipment will be a type which will efficiently remove all loosened material and load into trucks for hauling and spreading. Because of the nature of the streets to be ground and the traffic restrictions, a belt loader followed by a power sweeper and manual sweeper is the most desirable method. Flushing into the City's stormwater system as a means of cleanup will not be allowed. 503. Concrete Pavement The installation of concrete pavement, including materials, equipment, foundation and construction methods will be in conformance with Section 412, Portland Cement, Concrete Pavement, of the CDOT Highways Standard Specifications for Road and Bridge Construction, except as modified herein or as modified with the approval of the City Engineer. Specifications for concrete work, Section 600, Concrete Work, of these Standards and Specifications, must be followed. Concrete pavements will be installed as shown on the accepted plans or as approved by the City Engineer. When concrete pavement is constructed on a curve, flexible forms will be used having a radius of 200 feet or less, unless otherwise directed by the City Engineer. The Contractor will furnish steel pins to use in setting grades for concrete pavement. 503.1. Portland Cement-Treated Base In those instances where deemed necessary by a qualified Soils Engineer and accepted by the City Engineer, Portland Cement treated base may be required. When required, this base shall comply with Section 308, Portland Cement Treated Base, of the CDOT Standard Specifications for Roads and Bridge Construction. ---PAGE BREAK--- Standards and Specifications Section 500 Street Construction Page 9 504. Appurtenant Concrete Structures Curb, curb ramps, gutter, sidewalk, cross pan and driveway construction will conform to all applicable provisions of these Standards and Specifications and Standard Drawings No. 1400-10 through No. 1400-15. Concrete specifications are contained in Section 600. 504.1. General Requirements 504.1.1. Curbs and Gutters The section to be constructed will be as identified on the approved plans or as shown on Standard Drawings No. 1400-10 through No. 1400-15. 504.1.2. Sidewalks Sidewalks will be 4 inches thick where detached or 6 inches thick where attached, unless noted otherwise on the accepted plans and shall be constructed to the dimensions shown on the accepted plans. See Standard Drawing No.1400-11. All areas of sidewalk that are driveways or are in parks, open spaces or greenbelts will be constructed with 6 inch thick concrete. Six inch thick sidewalks may be constructed in other areas as required by the City Engineer. 504.1.3. Crosspans and Curb Return Fillets Cross pans and curb return fillets will be constructed 8 inches thick with #4 reinforcing bars (place at 18 inch centers, each way) in residential, commercial and industrial areas. Typical cross pan sections are shown on Standard Drawing No. 1400-13. Where unusual conditions prevail, additional reinforcing steel and special joints may be required by the City Engineer. 504.1.4. Curb Cuts and Driveways Curb cuts in 6 inch vertical curbs will be provided at all driveway locations, as shown on the accepted plans. Construction of curb cuts will be as shown on Standard Drawing No. 1400- 14. Spacing will be as shown on Standard Drawing No. 1400-10. 504.1.5. Curb Ramps Curb ramps for the handicapped will be installed at all street corners and at locations designated by the City Engineer. Curb ramps will be constructed as shown on CDOT Standard Drawings, M-608-1, Type 2 or Type 3. 504.2. Construction Requirements 504.2.1. Staking and Grade Control Control and construction stakes will be set by field parties under the supervision of a Registered Professional Engineer or a Registered Land Surveyor licensed to practice in Colorado who shall be paid by the Contractor. A set of accepted plans will be kept on the job site at all times by the Contractor. It will be the responsibility of the Contractor to maintain the grade and alignment as shown on the accepted plans. The alignment and grade elevation of forms will be checked and any ---PAGE BREAK--- Standards and Specifications Section 500 Street Construction Page 10 necessary corrections will be made before placing the concrete. When any form has been disturbed or any subgrade thereunder has become unstable, the form will be reset and rechecked after the subgrade has been replaced or recompacted. 504.2.2. Excavation and Embankment Excavation or fill will be made to the required grade and the base on which the curbing section is to be set will be compacted to a smooth, even surface. All material placed in fill and the top 6 inches of the subgrade in cut sections will be compacted to at least 95% of maximum dry density as determined by ASTM D-698. A proof roll is required on sidewalk subgrade (Sec. 501.1). Where spongy or unsuitable materials are encountered which will not provide a stable subgrade, the material will be removed and replaced with suitable material and compacted to the specified density. The subgrade will be compacted within the forms by a vibratory compactor or other approved method whenever any loose subgrade material is present. Immediately prior to placing the concrete, the subgrade will be tested for conformity to the specified cross section. Materials will be removed or added to bring all portions of the subgrade to the correct elevation. The subgrade will be thoroughly compacted and again tested for proper cross section. Concrete will not be placed on any portion of the subgrade that has not been inspected by the City Engineer for correct elevation and proper compaction. The subgrade will also be cleared of any loose material that may have fallen on it. 505. Inspection Refer to Section 104, Inspections, of these Standards and Specifications. 505.1. Required Inspections Adequate inspections assure compliance to City requirements and are the basis for the City's recommendation that said streets be accepted for maintenance and for release of performance guarantees. It is the responsibility of the Contractor to contact the City Engineer a minimum of one working day in advance of the required inspections. Required inspections include: a. Culverts - trenching, grade, bedding, installation, backfill and compaction. Inspection to be requested when backfill is completed to one-half (1/2) the depth of the culvert. b. Concrete - finished excavation, grade, forming, reinforcing steel. c. Structures - concrete pour, surface finish and test cylinders. Three inspections are required: 1) prior to placing steel; 2) prior to concrete pour; and 3) during and after final pour. d. Street - four inspections are required; 1) subgrade; 2) base course; 3) prime; and 4) paving, all of which are required prior to proceeding with the next phase. Locations of required samples for testing will be designated by the City Engineer. e. Final - a request for the final inspection and acceptance for maintenance or release from performance guarantee may be made only after all preceding inspections have been passed. ---PAGE BREAK--- Standards and Specifications Section 500 Street Construction Page 11 f. Utilities - manholes, valve boxes, inlets, etc. 505.2. Required Testing When required by the City Engineer, a Professional Engineer will certify the quality of materials or construction. All testing will be by recognized methods as specified in these Standards and Specifications and will be at the Contractor's expense. 505.3. Utility Installations Prior to the installation of street subgrade, base, paving, and concrete materials, utility installations will be made, service lines stubbed beyond the right-of-way line and all trenches will be backfilled and properly compacted. Utility repair patches shall be in accordance with drawings 500-1 or 500-2 depending on size. 505.4. Street Lighting At the time of inspection, all street lights will be in place as shown on the approved plans and will be operating as set forth in Section 701.5, Street Lighting Procedure, of these Standards and Specifications. 506. Street Landscaping Landscaping shall be installed in accordance with per approved landscape plan. See Lafayette Code for specific design and water use requirements. ---PAGE BREAK--- Standards and Specifications Section 600 Concrete Work Page 1 Section 600 Concrete Work 600. CONCRETE 2 600.1. . 2 600.2. MATERIALS 2 600.2.1. Cement 2 600.2.2. Fly 2 600.2.3. 3 600.2.4. Admixtures 3 600.2.5. Fine Aggregate 3 600.2.6. Coarse Aggregate 3 600.2.7. Color Patterned 4 600.3. MIXING 4 600.3.1. General 4 600.3.2. Design of the 4 600.3.3. Ready-Mixed 4 600.4. REINFORCING STEEL AND 5 600.4.1. Fibrous 7 600.5. PLACING 7 600.5.1. General 7 600.5.2. 8 600.5.3. 8 600.5.4. Color Patterned 8 600.6. JOINTS 9 600.6.1. 9 600.6.2. Spacing 9 600.7. FINISHING AND CURING 600.8. PROTECTION 600.8.1. Cold Weather Concreting 600.8.2. Hot Weather Concreting 600.9. MISCELLANEOUS 600.9.1. Repairs 600.9.2. Cleanup 600.9.3. Backfilling 600.9.4. Testing Drawings 600-1 Curb & Gutter Joint Detail ---PAGE BREAK--- Standards and Specifications Section 600 Concrete Work Page 2 600. Concrete Work 600.1. General All Portland Cement concrete work within any street, alley right-of-way, water system, sewage system, or storm drainage system of the City will meet the requirements of these Standards and Specifications. Engineering, plans, licenses, permits, inspection, warranties and acceptance will be as detailed in these applicable Standards and Specifications for the type of construction involved. Permits will be obtained before work begins. The Contractor will call for form inspection, giving one working day notice, and inspection will be made before placement of concrete can occur. Written notice of rejection will be given to Contractor in the event any aforementioned conditions given by the City Engineer are not met, and work shall be halted until such time as corrective action is taken. Copies of the accepted drawings and the permit shall be on the job site and available to the inspector. 600.2. Materials Concrete will be composed of Portland Cement, aggregate, water and air. Concrete shall be reinforced with steel bars, wire fabric or fibers where required. Admixtures other than air-entraining agents require written permission of the City Engineer. 600.2.1. Cement All cement used in concrete work shall be Portland Cement conforming to the requirements of ASTM C-150, Type I or Type II. In general, cement meeting the requirements of ASTM C-150 Type II cement shall be used in concrete that will be in contact with the soil, unless otherwise allowed or directed by the City Engineer. Cement, which for any reason has become partially set or which contains lumps of caked cement, shall be rejected. The Contractor will be responsible for the proper storage of all cement until it is used. When requested by the City Engineer, the Contractor will, at his own cost and expense, furnish the City Engineer with a certificate from the manufacturer or an acceptable testing laboratory for each carload of cement from which cement is taken for use in the work, stating that the cement meets the requirements of these Standards and Specifications for Portland Cement. 600.2.2. Fly Ash Fly ash may be utilized in the design mix when allowed by the City Engineer. Fly ash shall conform to the requirements of ASTM C 618 for Class C or Class F. Class C fly ash will not be permitted where sulfate-resistant cement is required. The contractor shall notify the City Engineer of the source of the fly ash for review prior to use in the project. The fly ash to be used on any project shall have been tested for ---PAGE BREAK--- Standards and Specifications Section 600 Concrete Work Page 3 compliance with these specifications. The results of this testing shall be submitted to the City Engineer prior to its use on the project. 600.2.3. Water Water for concrete will be clean and free from sand, oil, acid, alkali, organic matter, or other deleterious substances and will meet the requirements for mix water as published in ASTM C 94. Water from potable public supplies or water that has been proven to be suitable for drinking is satisfactory. 600.2.4. Admixtures The Contractor will use air-entraining admixtures in all exposed concrete. Air entraining admixtures shall meet AASHTO M-154. 600.2.5. Fine Aggregate Fine aggregate will be composed of clean, hard, durable, uncoated particles of sand, free from injurious amounts of clay, dust, soft or flaky particles, loam, shale, alkali, organic matter or other deleterious matter. Fine aggregate will be well graded from coarse to fine and when tested by means of laboratory sieves will meet the requirements of AASHTO M-6 (alternate CDOT Section 703). Sieve Size Percent Passing 3/8" 100 #4 95 - 100 #16 45 - 80 #50 10 - 30 #100 2 - 10 600.2.6. Coarse Aggregate The coarse aggregate will consist of broken stone or gravel composed of clean, hard, tough and durable stone and will be free from soft, thin, elongated or laminated pieces, disintegrated stone, clay, loam, vegetable or other deleterious matter. Coarse aggregate will be well graded and when tested by means of laboratory sieves will meet the requirements of AASHTO M-43 No. 467 (alternate CDOT Section 703). Sieve Size Percent Passing 2" 100 1-1/2" 95 - 100 3/4" 35 - 70 3/8" 10 - 30 #8 0 - 5 ---PAGE BREAK--- Standards and Specifications Section 600 Concrete Work Page 4 600.2.7. Color Patterned Concrete Where required on the accepted plans, colored patterned concrete shall comply with all applicable portions of this Section 600. In addition, the following shall apply: a. Minimum 28-day compressive strength of concrete shall be 3,000 psi. b. Air entrainment shall be 6% for maximum aggregate size of ¾ inch or 1 inch and shall be 7.5% for a maximum aggregate size of ⅜ inch or ½ inch. c. Normal set or retarded set water reducing admixture shall comply with ASTM C 494. d. No calcium chloride shall be added to the concrete mix. e. Matching integral color shall be used as a supplement but not as a color hardener. f. Color hardener: Specially formulated for installation of pattern concrete, grade "Heavy Duty.” Color shall be as noted on the accepted drawings or as approved by the City Engineer. g. Color curing compound shall comply with ASTM C 309 and with all applicable air pollution regulations. 600.3. Mixing 600.3.1. General All concrete will be thoroughly mixed in a batch mixer of an approved type and capacity. The drum shall rotate at least 20 revolutions on charging or traveling and 50 to 100 revolutions at mixing speed on site prior to discharge. During the period of mixing, the drum will be operated at the speed specified by the manufacturer of the equipment. The entire contents of the mixer will be discharged before recharge and the mixer will be cleaned frequently. The concrete will be mixed only in such quantities that are required for immediate use. No retempering of concrete will be permitted. Hand-mixed concrete will not be permitted except by written approval of the City Engineer and then in only very small quantities or in case of an emergency. Truck washout water may not enter the City storm water system. 600.3.2. Design of the Mix 600.3.2.1. General Concrete mix information shall be prepared and submitted to the City Engineer for review and acceptance. No concrete will be incorporated into the work until the proportions have been accepted by the City Engineer. 600.3.2.2. Strength Concrete for flatwork shall have a minimum 28-day compressive strength of 4,000 psi. Structural concrete shall be provided as specified on the approved plans. 600.3.3. Ready-Mixed Concrete The use of ready-mixed concrete will in no way relieve the Contractor or Developer of the responsibility for proportion, mix, delivery or placement of concrete; all concrete must ---PAGE BREAK--- Standards and Specifications Section 600 Concrete Work Page 5 conform to all requirements CDOT Section 601. The information included on the delivery system should be in accordance with CDOT Section 601. Concrete will be continuously mixed or agitated from the time the water is added until the time of use and will be completely discharged from the truck mixer or truck agitator within 1½ hours after it comes in contact with the mixing water. Retempered concrete will not be allowed. The City will have free access to the mixing plant at all times. The organization supplying the concrete will have sufficient plant and transportation facilities to assure continuous delivery of the concrete at the required rate. (The contractor will collect delivery, or batch, tickets from the driver for all concrete used on the project and deliver them to the City Engineer.) Batch tickets will provide the following information in accordance with ASTM C-94: a. Name of ready-mix batch plant b. Serial number of ticket c. Date d. Truck number e. Name of purchaser f. Specific designation of job (name and location) g. Specific class or designation of the concrete in conformance with that employed in job specifications h. Amount of concrete in cubic yards i. Time loaded or of first mixing of cement and aggregates j. Water added by receiver of concrete and his initials k. Weights of fine and coarse aggregates l. Type, brand and amount of cement m. Type, brand and amount of admixtures n. Quantity of water including surface water on aggregates 600.4. Reinforcing Steel and Forms The placing, fastening, splicing and supporting of reinforcing steel and wire mesh or bar mat reinforcement shall be in accordance with the plans and the latest edition of CRSI Recommended Practice for Placing Reinforcing Bars. Before being positioned, all reinforcing steel will be thoroughly cleaned of mill and rust scale and of coatings that will destroy or reduce the bond. Where there is delay in depositing concrete, reinforcement will be reinspected and, if necessary, cleaned. Reinforcement will be carefully formed to the dimensions indicated on the accepted plans by the cold bending method. Cold bends will be made so that the inside diameter of the bend measured on the inside of the bar shall be as follows: ---PAGE BREAK--- Standards and Specifications Section 600 Concrete Work Page 6 Bar Size Grade 60 #3 through #8 6 bar diameter #10 and #11 8 bar diameter #14 and #18 10 bar diameter The inside diameter of bend for stirrups and ties shall not be less than four bar diameters for sizes #5 and smaller and five bar diameters for #6 and #8 inclusive. Reinforcement shall not be bent or straightened in a manner that will injure the material. Bars with kinks or bends not shown on the plans will not be used. Heating of reinforcement will not be permitted. Reinforcing steel will be accurately placed and secured against displacement by using annealed iron wire of not less than No.18 gauge or by suitable clips at intersections. Where necessary, reinforcing steel will be supported by metal chairs or spacers, precast mortar blocks or metal hangers. Splicing of bars, except where shown on the plans, will not be permitted without approval of the City Engineer. Welded wire fabric for concrete reinforcement will be of the gauge, spacing, dimensions and form specified on the plans or detailed drawings and will comply with Specifications for Welded Steel Wire Fabric for Concrete Reinforcement (ASTM A-185) or Specification for Welded Deformed Steel Wire Fabric for Concrete Reinforcement (ASTM A-497). Contractor will submit shop drawings of the reinforcement to the City Engineer for his review and acceptance. The City Engineer's acceptance of shop drawings and bar schedules will not relieve the contractor of fulfilling his responsibilities as outlined in the plans and specifications of the contract. Unless otherwise shown on the plans, the minimum clear cover for reinforcing steel will be the following, which is specified in ACI 301, Sec. 5.5: Bottom bars on soil bearing foundations & slabs 3 inches Bars adjacent to surfaces exposed to weather or earth backfill: For bars larger than #6 2 inches For #6 or smaller 1-1/2 inches Interior Surfaces: slabs, walls, joints with #12 or smaller. 3/4 inches Whenever necessary, forms will be used to confine the concrete and shape it to the required lines. Forms will have sufficient strength to withstand, without deformation, the pressure resulting from placement and vibration of the concrete. Forms will be constructed so that the finished concrete will conform to the shapes, lines, grades and dimensions indicated on the accepted plans. Any form which is not clean and has not had the surface prepared with a commercial form oil that will effectively prevent bonding and that will not stain or soften concrete surfaces will not be used. ---PAGE BREAK--- Standards and Specifications Section 600 Concrete Work Page 7 Plywood forms, plastic coated plywood forms or steel forms will be used for all surfaces requiring forming that are exposed to view, whether inside or outside any structure. Surfaces against backfilled earth, interior surfaces of covered channels or other places permanently obscured from view may be formed with forms having substandard surfaces. Forms will not be disturbed until the concrete has hardened sufficiently to permit their removal without damaging the concrete or until the forms are not required to protect the concrete from mechanical damage. Minimum time before removal of forms after placing concrete will be one day for footings and Class concrete, two days for all other concrete except in curbs, gutters and sidewalks. 600.4.1. Fibrous Reinforcing When shown on the accepted plans or approved by the City Engineer, fibrous reinforcing may be used. Fibrous concrete reinforcement shall be 100% virgin polypropylene fibrillated fibers specifically manufactured for use as concrete reinforcement, containing no reprocessed olefin materials. Fibers shall be Fibermesh InForce by Industries or approved equal. The fibers shall have the following physical characteristics: a. Specific gravity - 0.91 b. Fiber length - per manufacturer's recommendation for specific use ( ¾ inch for sidewalks) Add fibrous concrete reinforcement to concrete materials at the time the concrete is batched in the amounts recommended by the manufacturer (1.5 lb/cubic yard minimum) or as indicated on the accepted plans. Concrete shall be mixed in strict accordance with the fibrous concrete reinforcement manufacturer's instructions and recommendations to assure uniform and complete dispersion. 600.5. Placing Concrete 600.5.1. General Before depositing concrete, debris will be removed from the space to be occupied by the concrete and the forms, including any existing concrete surfaces, will be thoroughly wetted. Concrete will not be placed until all forms and reinforcing steel have been inspected and accepted by the City Engineer. Concrete will be handled from the mixer to the place of final deposit as rapidly as possible by methods which prevent separation or loss of ingredients. The concrete will be deposited in the forms as nearly as practicable in its final position to avoid rehandling. It will be deposited in continuous layers, the thickness of which generally will not exceed 12 inches. Concrete will be placed in a manner that will avoid segregation and will not be dropped freely more than 5 feet. If segregation occurs, the City Engineer may require the concrete to be removed and replaced at the Contractor's expense. Concrete will be placed in one continuous operation, except where keyed construction joints are shown on the plans or as approved by the City Engineer. Delays in excess of 30 minutes may require removal and replacement of that pour, as determined by the City Engineer. ---PAGE BREAK--- Standards and Specifications Section 600 Concrete Work Page 8 600.5.2. Vibrating Concrete will be thoroughly compacted or vibrated. All concrete will be compacted by internal vibration using mechanical vibrating equipment, except that concrete in floor slabs, sidewalks or curb and gutter, not poured against form linings, will be either tamped or vibrated. Care will be taken in vibrating the concrete to vibrate only long enough to bring a continuous film of mortar to the surface. Vibration will stop before any segregation of the concrete occurs. Mechanical vibrators will be an approved type as specified in ACI Publication 309, Chapter 5. Vibrators will not be used to move or spread the concrete. Any evidence of lack of consolidation or overconsolidation will be regarded as sufficient reason to require the removal of the section involved and its replacement with new concrete at the Contractor's expense. The Contractor will be responsible for any defects in the quality and appearance of the completed work. 600.5.3. Workability The consistency of concrete will be kept uniform for each class of work and will be checked by means of slump tests. The workability of the concrete will be varied as directed by the City Engineer. At all times concrete will have a consistency such that it can be worked into corners and angles of the forms and around joints, dowels and tie-bars by the construction methods which are being used without excessive spading, segregation or undue accumulation of water or laitance on the surface. If, through accident, intention or error in mixing, any concrete fails to conform to the proportions of the approved mix design, such concrete will not be incorporated in the work but will be discarded off the project site as waste material at the Contractor's expense. No water may be added at the job site without permission of the City Engineer. If approval is obtained and water is added at the job site, slump tests will be run and test cylinders cast following the addition of the water. Any expense incurred in excess of ordinary tests will be borne by the Contractor. 600.5.4. Color Patterned Concrete Special concrete mix with integral color shall be placed and screeded to the proper grade and floated to a uniform surface in the normal manner for slabs on grade. Color hardener shall be applied evenly to the plastic surface by the dry shake method using a minimum of 60 pounds per 100 square feet. Color hardener shall be applied in two or more shakes, floated after each and troweled only after the final floating. While the concrete is still plastic, the imprinting tools shall be applied to make the desired patterned surface. The pattern shall be matched at imprint edges and joints. Color Curing Compound, thinned in the proportion of one part cure to one part mineral spirits (paint thinner), shall then be applied uniformly with a roller or sprayer. The coverage shall be approximately 600 to 650 square feet per gallon of unthinned curing compound. At times when the air temperature is at or near freezing, the slab shall instead be cured using a suitable curing blanket and, if possible, the slab shall later be sealed with the Color Curing Compound at such time as the air temperature is above freezing. ---PAGE BREAK--- Standards and Specifications Section 600 Concrete Work Page 9 600.6. Joints 600.6.1. Materials Joint materials will conform to AASHTO Specifications according to type as follows: Concrete joint sealer, hot-poured elastic M 173 Preformed expansion joint filler (Bituminous Type) M 33 Preformed sponge rubber and cork expansion joint fillers M 153 Preformed expansion joint fillers - nonextruding & resilient bitum. M 213 Non-bituminous types shall be placed in widths shown on the accepted plans or 3/8" when not specified. Bituminous type shall be used for concrete paving and structural construction where joint sealers are not called for. 600.6.2. Spacing 600.6.2.1. Expansion Joints Expansion joint material will be provided at the following locations and will be in place prior to the placing of concrete: a. at each end of curb return; b. at both edges of driveway; c. between back of sidewalk and driveway slab or service walk; d. between new concrete and existing masonry buildings; e. as shown on the drawings; f. as directed by the City Engineer; g. between new and existing concrete; and h. every 100 feet of sidewalk. Refer to Standard Drawing 600-1 for expansion joint details. 600.6.2.2. Contraction Joints Transverse joints will be placed at maximum intervals of ten feet to control random cracking; joints will be formed, sawed or tooled to a minimum depth of 1/3 of the total thickness (no less than 2 inches). If divider plates are used, the maximum depth of plates will not be greater than one-half depth at the finished surface and will be no less than 15/16 inch thick. Refer to Standard Drawing 600-1 for contraction joint details. 600.6.2.3. Tool Joints Tool joints will be spaced as follows: a. not more than 10 feet nor less than 5 feet apart in curb and gutter and combination curb-walk; b. not more than 10 feet nor less than 5 feet apart in sidewalk; c. at least two joints, equally spaced at not greater than 10 foot intervals as applicable in driveways; d. or as directed by the City Engineer. ---PAGE BREAK--- Standards and Specifications Section 600 Concrete Work Page 10 600.7. Finishing and Curing Exposed faces of curbs and sidewalks will be finished to true-line and grade as shown on the plans. Surface will be floated to a smooth but not slippery finish. Sidewalk and curb will be broomed or combed and edged unless otherwise indicated by the City Engineer. After completion of brooming and before concrete has taken its initial set, all edges in contact with the forms will be tooled with an edger having a 3/8 inch radius. No dusting or topping of the surface or sprinkling with water to facilitate finishing will be permitted. Immediately following the removal of the forms, all fins and irregular projections will be removed from all surfaces except from those which are not to be exposed or are not to be waterproofed. On all surfaces, the cavities produced by form ties, honeycomb spots, broken corners or edges and other defects, shall be thoroughly cleaned, moistened with water and carefully pointed and trued with a mortar consisting of cement and fine aggregate. The surface will be left sound, smooth, even and uniform in color. Mortar used in pointing will not be more than 30 minutes old. All construction and expansion joints in the completed work will be left carefully tooled and free of all mortar and concrete. The joint filler will be left exposed for its full length with clean and true edges. Fresh concrete will be adequately protected from weather damage and mechanical injury during the curing periods. Curing processes described herein may be used at the option of the City Engineer. The selected curing process will be started as soon as it can be done without injury to the concrete surface. The use of a membrane curing compound is recommended. The following curing procedures may be used subject to the approval of the City Engineer: a. Ponding (for slabs or footings) b. Spraying c. Wet burlap, earth or cotton mats d. Waterproof paper or polyethylene plastic cover Membrane curing compound will not be used when the concrete surface will be painted. The type of membrane curing compound chosen will not permanently discolor the concrete surface. Where membrane curing compound is not used, the curing process will be carefully adhered to as follows: a. Surfaces being wetted by ponding, spraying or wetted material will be kept completely wetted, with an excess of free water on the surface, at all times for the first 72 hours. After this period, but for the remaining four days, a wetting schedule will be followed whereby the concrete is wetted on a schedule approved by the City Engineer. b. Surfaces being protected by waterproof paper or polyethylene plastic cover will receive special attention during the first 72 hours to insure there is actually free moisture on the surface of the concrete under the waterproof surface. The City Engineer may require the removal of the cover and a wetting of the surface ---PAGE BREAK--- Standards and Specifications Section 600 Concrete Work Page 11 when, in his judgment, there is insufficient moisture for curing. After the first 72 hours the cover will be kept in place for the remainder of the curing period. 600.8. Protection 600.8.1. Cold Weather Concreting During extreme weather conditions, placing of concrete will be permitted only when the temperature of the concrete placed in the forms will not be less than 60ºF nor more than 90ºF. To maintain this temperature range, the Contractor will provide acceptable heating apparatus for heating the aggregates and the water. Cold weather placement of concrete shall follow the requirements and recommendations of ACI Manual 306. Concrete may be placed when the air temperature in the shade is 40ºF and rising. No concrete will be placed, regardless of the present temperature, when the weather forecast promises freezing weather before final set of the concrete unless special means of heating and protection are used. Protection against freezing is the Contractor's responsibility regardless of the weather forecast or climatic conditions at the time of placement. Small structures and slabs may be protected by completely covering fresh concrete with dry straw, canvas or blankets to a depth that insures protection. Large structures or vertical walls will be protected against freezing by enclosing the structure and heating with salamanders, heaters or other devices capable of providing uniform and even heat throughout the structure. Heaters must be vented so that combustion gases are exhausted outside the enclosure in order to avoid carbonation of the fresh concrete. Cold weather is defined as a period when, for more than three consecutive days, the following conditions exist: • The average air temperature is less than 40ºF, and • The air temperature is not greater than 50ºF for more than one half of any 24-hour period. Concrete placed in cold weather will be protected from extreme temperatures as follows: a. A temperature of at least 50ºF for the first 72 hours will be maintained. b. After the first 72 hours and until the concrete is 7 days old, it will be protected from freezing temperatures. c. Concrete adjacent to heaters or salamanders will be insulated from direct heat of the unit which may dry it out prior to being properly cured. d. Temperatures will be measured by maximum and minimum thermometers furnished by the Contractor and installed adjacent to the concrete. Concrete slabs will not be placed, regardless of temperature conditions, if the supporting ground is frozen or contains frost. Use of salt or other additives to prevent concrete from ---PAGE BREAK--- Standards and Specifications Section 600 Concrete Work Page 12 freezing is not allowed. Concrete which has been frozen will be completely removed and replaced as directed by and to the satisfaction of the City Engineer. TABLE 600-1 MINIMUM CONCRETE TEMPERATURE AS MIXED FOR INDICATED AIR TEMPERATURE Air Temperature Section Size, Minimum Dimension (Inches) < 12 in. 12-36 in. Above 30°F 60°F 55°F 0°F-30°F 65°F 60°F Below 0°F 70°F 65°F Minimum Concrete Temperature As Placed And Maintained 55°F 50°F 600.8.2. Hot Weather Concreting Except by written authorization, concrete will not be placed if the temperature of the plastic concrete cannot be maintained at 90ºF or lower. The placement of concrete in hot weather shall comply with ACI 305. 600.9. Miscellaneous 600.9.1. Repairs After stripping of the forms, if any concrete is found to be not formed as shown on the accepted plans or is out of alignment or level or shows a defective surface, it will be considered as not conforming with the intent of these Standards and Specifications and will be removed and replaced by the Contractor at his expense unless the City Engineer gives written permission to patch the defective area. In this case, patching will be done as described in the following paragraphs. Defects that require replacement or repair are those that contain honeycomb, damage due to stripping of forms, loose pieces of concrete, bolt- holes, tie-rod holes, uneven or excessive ridges at form joints and bulges due to movement of the forms. Ridges and bulges will be removed by grinding. Honeycombed and other defective concrete that does not affect the integrity of the structure will be chipped out and the vacated areas will be filled. The repaired area will be patched with a non-shrink, non- metallic grout with a minimum compressive strength of 5,000 psi in 28 days. All repaired areas shall be treated with an epoxy bonding agent. Bolt-holes, tie-rod holes and minor imperfections, as approved by the City Engineer, will be filled with dry-patching mortar composed of one part Portland cement to two parts of regular concrete sand (volume measurement) and only enough water so that after the ingredients are mixed thoroughly, the mortar will stick together on being molded. Mortar repairs will be placed in layers and thoroughly compacted by suitable tools. Care will be ---PAGE BREAK--- Standards and Specifications Section 600 Concrete Work Page 13 taken in filling rod and bolt holes so that the entire depth of the hole is completely filled with compacted mortar. The mortar mix proportions described above are approximate. Where repairs are made in existing sidewalks, all edges of the old sidewalk allowed to remain will be sawcut. No rough edges will be permitted where new construction joins the old section. Unless directed by the City Engineer, no section less than 6 feet in length will be placed or left in place. Where new sidewalk construction abuts existing sidewalks, the work will be accomplished so that there is no abrupt change in grade between the old section and the new work. 600.9.2. Cleanup The exposed surfaces of the concrete will be thoroughly cleaned upon completion of the work and the site will be left in a neat and orderly condition. 600.9.3. Backfilling When side forms are removed and the concrete has gained sufficient strength, the space adjoining the concrete will be backfilled with suitable material, properly compacted and brought flush with the surface of the concrete and adjoining ground surface. In embankments, the backfill will be level with the top of the concrete for at least two feet and then sloped as shown on the accepted plans or as directed by the City Engineer. Existing pavement which is damaged during construction will be repaired by the Contractor at his expense. The first foot of patching to match existing asphalt or concrete will be the Contractor's responsibility. 600.9.4. Testing 600.9.4.1. General The requirements of this section will apply to testing services for all concrete curb and gutter, sidewalk, pavement, slope paving, retaining walls, structures and for all miscellaneous concrete testing. Concrete materials and operations will be tested as directed by the City Engineer and as herein stipulated. The required testing services will be performed by a designated testing agency acceptable to the City Engineer and all testing agencies will meet the requirements of ASTM E329. A representative of the testing agency will inspect, sample and test material and production of concrete as required by the City Engineer. When it appears that any material furnished or work performed by the Contractor fails to fulfill specification requirements, the testing agency will report such deficiency to the City Engineer and the Contractor. The testing agency will report all test and inspection results to the City Engineer and Contractor immediately after they are performed. All test reports will include the exact location of the work at which the batch represented by a test was deposited. The report of the strength test will include detailed information on storage and curing of specimen prior to ---PAGE BREAK--- Standards and Specifications Section 600 Concrete Work Page 14 testing, the project number and the location of the concrete (curb, manhole, inlet, sidewalk, paving, etc.). The testing agency or its representative is not authorized to revoke, alter, relax, enlarge or release any requirements of these Standards and Specifications, nor approve or accept any portion of the work. 600.9.4.2. Tests Provided by the Contractor The following services shall be performed by the designated testing agency at the expense of the Contractor or Developer: a. Conduct strength test of the concrete during construction in accordance with the following procedure: Secure composite samples in accordance with AASHTO T141; mold and cure specimens from each sample in accordance with AASHTO T23. The maximum time between sampling and casting the cylinders or beams shall be 45 minutes. If they cannot be returned to the laboratory and cast within the 45 minutes, they will be cast in the field and transported to the laboratory in 12 to 24 hours. One test series will be taken per 50 cubic yards (or fraction thereof) of the concrete placed per day or as directed by the City Engineer. 1) Field cured test series: Four cylinders: 1 to be broken at 7, and 2 at 28 days; 1 for a spare 2) Lab cured test series: Six cylinders: 1 to be broken at 7 days; 2 to be broken at 28 days*; 1 to be broken at 45 days if necessary *If the specified strength is not obtained at 28 days, 2 cylinders are to be broken at 45 days. b. Determine slump of the concrete sample of each strength test whenever consistency of concrete appears to vary or when directed by the City Engineer, in accordance with AASHTO T119. c. Determine air content of the concrete sample for each strength test in accordance with either AASHTO T152 (pressure method), T196 (volumetric method) or T121 (gravimetric method). d. Sample additional concrete at point of placement and perform other testing or inspection service as required. e. When required by the City Engineer, the Contractor or Developer will provide concrete mix designs, the results of which will be immediately reported to the City Engineer. When pumped concrete is to be used, a separate mix design will be required. Mix designs will be in accordance with ACI 211 and 304, as applicable. f. Additional testing and inspection will be required when there are changes in materials or proportions. g. When the work fails to pass inspection or previous tests fail to meet specifications, additional tests will be taken as directed by the City Engineer. h. Core samples will be obtained and tested when samples of fresh concrete were not obtained and tested in accordance with the provisions of these Standards and Specifications. Obtaining and testing cores will be in accordance with ASTM C42. Concrete in the area represented by a core test will be considered adequate if the ---PAGE BREAK--- Standards and Specifications Section 600 Concrete Work Page 15 average strength of the cores is equal to at least 85% of the specified strength f'c and if no single core is less than 75% of the specified strength. Core holes will be filled with low slump concrete or mortar. Cores may be tested in the dry condition in accordance with ACI 301. i. Failure of the Contractor to furnish testing as herein described will be sufficient cause for rejection of the work in question. 600.9.4.3. Responsibility and Duties of the Contractor The Contractor will provide the testing agency with the following: a. Any labor necessary to assist the designated testing agency in obtaining and handling samples at the project or from other sources of material. b. Adequate and properly maintained facilities for safe storage and proper curing of concrete test specimens on the project site as required by AASHTO T23. The use of testing services shall not relieve the Contractor of the responsibility to furnish material and construct in full compliance with these Standards and Specifications. ---PAGE BREAK--- Standards and Specifications Section 700 Traffic Control Devices, Signs, and Street Lighting Page 1 Section 700 Traffic Control Devices, Signs, and Street Lighting Rev 08-30-2012 700. TRAFFIC CONTROL DEVICES AND STREET LIGHTING 2 700.1. . 2 701. TRAFFIC CONTROL DEVICES 2 701.1. . 2 701.2. SIGNS 2 701.2.1. Street Name Signs 2 701.2.2. Street Name Sign Blade Holder 2 701.2.3. Stop 3 701.2.4. Other Signs 3 701.3. STRIPING . 3 701.4. SIGN SUPPORTS 3 701.5. STREET LIGHTING PROCEDURE 4 702. TRAFFIC SIGNALS 4 702.1. REGULATIONS AND 4 702.2. INSPECTION 4 702.3. TRAFFIC 5 702.4. EQUIPMENT LIST AND 5 702.5. COORDINATION WITH OTHER AGENCIES AND 5 702.6. 6 702.7. CONDUIT . 6 702.7.1. General 6 702.7.2. 6 702.7.3. 6 702.8. CABLE AND 8 702.8.1. General 8 702.8.2. Multiconductor 8 702.8.3. Installation Methods – Wiring 8 702.8.4. Connections to Signalheads, Pushbuttons and Traffic Controllers 702.8.5. Wire Splicing 702.8.6. Wire Bonding and Grounding 702.9. TRAFFIC SIGNAL CONTROLLERS 702.9.1. Actuated Controllers 702.9.2. Cabinet Foundations 702.9.3. Cabinet Locations Drawings 700-1 Street Lights ---PAGE BREAK--- Standards and Specifications Section 700 Traffic Control Devices, Signs, and Street Lighting Page 2 Section 700 Traffic Control Devices and Street Lighting 700. Traffic Control Devices and Street Lighting 700.1. General The installation of traffic control devices and street lighting shall comply with all applicable portions of the CDOT Standard Specifications for Road and Bridge Construction, the Manual on Uniform Traffic Control Devices and the accepted plans. These Standards and Specifications and any other requirements determined by the City Engineer will apply to all materials supplied and methods and procedures of work. 701. Traffic Control Devices 701.1. General Traffic control devices will be installed by the developer on all new streets accepted by the City for maintenance as set forth in these Standards and Specifications. Prior to installation of traffic control devices, underground utility locates shall be required. The developer or contractor shall submit a copy of the traffic device plan to the City Engineer for approval prior to installation. 701.2. Signs- All signs installed in the City of Lafayette shall meet the standards established in the current edition of the MUTCD. 701.2.1. Street Name Signs Street name signs will be furnished and installed by the contractor or developer and will be inspected by the City unless otherwise specified by the City Engineer. Sufficient signs and posts will be provided to allow installation on two corners of each intersection and will have white letters on a green background in conformance with the following dimensions: 1. All signs are to be constructed with 0.080 aluminum blanks, green engineer grade sheeting and white high intensity grade letters or numbers. 2. The street name blank shall be 8 inches in height, with 6 inch series C upper case and 4 inch series C lower case letters or numbers and 2 inch series C upper case prefix or suffix. 3. The length of the sign will vary due to the length of the street name. 4. One street name sign shall be provided for each particular named street. Signs made with sheeting and letters placed back to back on the same blank are required. 5. All lettering shall have Highway C font. 701.2.2. Street Name Sign Blade Holder No custom signs or posts are allowed in the City of Lafayette. ---PAGE BREAK--- Standards and Specifications Section 700 Traffic Control Devices, Signs, and Street Lighting Page 3 1. The blade holder shall be 5¼ inch square cup long style. It should be 2½ inch (for 2½x 2½ sq. post). It should have four places for 5/16 inch set screws. 2. The 90 degree crosspiece shall be 5¼ inch with two places for 5/16 inch set screws. 701.2.3. Stop Signs Stop signs shall be installed at all approaches to streets designated as through streets by the City as through streets. Stop signs shall be mounted on the same support posts as street name signs. All signs shall have high intensity grade sheeting and meet the MUTCD standard Highways Signs Manual Standard Dimensions Specifications. 701.2.4. Other Signs Speed limit signs, no parking signs, school signs and crosswalk signs and all other signs shall be installed at locations designated by the City Engineer. All signs shall have high intensity grade sheeting and meet the MUTCD Standard High Signs Manual Standard Dimensions Specifications. All stop or other signs shall be mounted with 3/8 inch rivets. 701.3. Striping The Contractor will submit a striping plan to the City Traffic Engineer for approval prior to beginning work. The striping plan will meet the requirements for such work as outlined in the Manual of Uniform Traffic Control Devices. Yellow centerline and lane line markings will be applied to streets designated by the City as collector or arterial streets. Standard 12- inch wide stop bars and crosswalks, as dimensioned below, will be provided at all stop locations and intersections adjacent to schools, parks, commercial and other areas as determined by the City. Markings will consist of preformed plastic material conforming to Section 713 of the CDOT Standard Specifications for Road and Bridge Construction. Crosswalks will be marked with 18 inch by 6 foot bars spread 4 feet apart. 701.4. Sign Supports All sign supports or posts will conform to specifications for perforated square steel tubing and to Standard Specifications for Cold Rolled Carbon Steel Sheets, Commercial Quality, ASTM Designation A-366. The cross section will be square and consist of twelve gauge steel (0.105" U.S.S. Gauge) carefully rolled to size and continuously welded at the corner and will conform to the following side dimensions: Post 2" x 2" x 12" Base 2¼" x 2¼" x 3" The finished members will be straight and will have a smooth, uniform finish. It will be possible to telescope consecutive sizes of tubes freely with a minimum amount of play. All holes and cut-off ends will be free from burrs. Seven-sixteenths inch diameter holes will be punched on one inch centers on all sides of the tube. Posts will be formed from cold rolled steel strip and then zinc coated (1.25 oz.) conforming to ASTM Specification A-525. All posts shall be attached to base with 3/8 inch rivets. ---PAGE BREAK--- Standards and Specifications Section 700 Traffic Control Devices, Signs, and Street Lighting Page 4 701.5. Street Lighting Procedure Xcel Energy will submit the street light layout to the City Engineer for review and approval. Developer will pay Xcel Energy the total costs of installation for all street lighting. Street lighting in residential areas will be pole top fixtures (Post Top Modern) with 70 watt high pressure sodium lamps on vertical, round, tapered black, aluminum or fiberglass poles. The mounting height shall not exceed 23 feet in residential areas. Any other luminaire style must have written approval of the City Engineer prior to installation or be a part of a PUD approval for a neighborhood style. In areas other than residential, street lighting will be archetype fixtures with high pressure sodium lamps on round tapered steel poles, black in color, with mast arms. The mounting height shall not exceed 40 feet. Any other luminaire style must have written approval of the City Engineer. The spacing shall generally be 300 to 400 feet or at intersections. 702. Traffic Signals 702.1. Regulations and Code Signal poles shall be designed in conformance with AASHTO Standard Specifications for Structural Supports for Highway Signs, Luminaires, and Traffic Signals. if the intersection is on City streets. Signals on the State highway system will be designed per CDOT M&S standards. All equipment will conform to the MUTCD for placement. In addition to requirements of the accepted plans, all material and work will conform to the requirements of the NEC and these Standards and Specifications. 702.2. Inspection Inspection of all material and work will be made by the City Engineer. All material delivered to the site will be subject to inspection, prior to or during installation, as deemed necessary by the City Engineer. The City Engineer may request samples of certain materials from the factory or warehouse for testing purposes prior to delivery on the site. Material that has been rejected by the City Engineer will not be delivered to the work site, and any material rejected at the work site will be immediately removed from the site. Failure by the City Engineer to note faulty material or workmanship during progress of the work will not relieve the Contractor of his responsibility for removing and/or replacing faulty materials at his own expense if any such materials are found at a later date. The signal design engineer will provide inspection and a certification letter that the signal has been built in substantial conformance with the plans and specifications and is operational. ---PAGE BREAK--- Standards and Specifications Section 700 Traffic Control Devices, Signs, and Street Lighting Page 5 Any work within the public right-of-way will require two working days (24 hours) prior notice to the City Engineer by the Contractor or Developer. 702.3. Traffic Control Refer to Section 103.1.8, Traffic Control, Barricades and Warning Sign, of these Standards and Specifications. 702.4. Equipment List and Drawings The Contractor will submit to the City, for review and acceptance, a listing of all materials and equipment that will be used in the work. The list will include the name of manufacturer, size and catalog number of unit, and will be supplemented by other required data, including detailed scale drawings and wiring diagrams of any nonstandard or special equipment and of any proposed deviation from the accepted plans. If required by the City Engineer, the Contractor will provide samples of materials proposed for use. All equipment listings and drawings will be submitted to the City Engineer for review and acceptance. Designs will be stamped by an Engineer licensed to work in the State of Colorado. No labor will be performed by the Contractor until the City Engineer has accepted all details and plans in writing to the Contractor. All applicable portions of Section 103.1, Protection of Public and Utility Interests, of these Standards and Specifications shall apply. The Contractor will furnish all materials, equipment and labor needed to install and maintain temporary traffic signals during progress of the work. All intersections presently signalized will be kept in operation until the new signal equipment is properly installed and ready for operation. If in the opinion of the City Engineer this is not possible because the installation of new equipment is in the same location as existing equipment, the Contractor will not proceed with any work which will cause the present equipment to become inoperative until he has all necessary replacement equipment on hand. Existing traffic signals will be kept in operation except when shut down due to changing over and connecting to new equipment. Work will be performed so that signals will be in operation at the close of each day's work, over weekends and during times when the Contractor is not working. When a signal is shut down, the City Engineer will be notified in writing two working days (48 hours) in advance of the proposed shut down. Major intersections will require uniformed traffic control during the periods of shut down. 702.5. Coordination with Other Agencies and Contractors It will be mandatory that the Contractor coordinate his conduit work with Xcel Energy to insure that all conduit installations and pull box installations are completed as quickly as possible. The Contractor may contract with Xcel Energy to install their conduits. ---PAGE BREAK--- Standards and Specifications Section 700 Traffic Control Devices, Signs, and Street Lighting Page 6 702.6. Maintenance The Contractor will maintain the work during construction and until the work is accepted by the City. 702.7. Conduit 702.7.1. General All conductors will be run in conduit except when run in metal poles. Conduit will be the rigid PVC type conforming to these Standards and Specifications. Conduit runs shown on the accepted plans are tentative as to routing and may be changed, as directed by the City Engineer, to avoid underground obstructions. Any change in location from those shown on the plans will require prior approval of the City Engineer and must be accurately recorded on as-built drawings in accordance with Section 105, Construction Plan Requirements, of these Standards and Specifications. Excavations for conduit will be 2 inches wider than the outside diameter of the conduit. Backfill for the conduit trenches will be compacted to 95% of the maximum proctor, ASTM 0698. A nylon pull string will be left in each conduit run for any future pulling of conductors. 702.7.2. Materials Rigid PVC conduit will be Schedule 40, Type 2, as specified in the NEC, and will be manufactured as high-impact type conforming to industry standards and commercial standard No. CS-207-60. Each length of conduit and all PVC fittings (expansion joints, coupling, adapter, etc.) will bear the label of Underwriters' Laboratories, Inc. Conduit will be the size or sizes indicated on the accepted plans. Rigid PVC conduit will be cut with a hacksaw and all ends squared and trimmed after cutting to remove rough edges. Connections will be the solvent weld type except where the connection is made to a steel conduit, in which case the coupling will be threaded on the metal conduit side. Solvent weld joints will conform to the PVC manufacturer's recommendations. Rigid PVC conduit will be used only for underground installations; all conduits used above ground will be the rigid galvanized steel type. A bare or green #10 AWG copper conductor will be run continuously in all conduit used for traffic signal circuits. This wire will be used for bonding and grounding purposes. Existing underground conduit that is incorporated into a new system will be cleaned and blown out with compressed air. 702.7.3. Installation Conduit will be laid to a depth of not less than 30 inches below the curb grade roadway construction. Conduits under railroad tracks will not be less than 42 inches below the bottom of the tie and/or as specified by railroad code. It will be the responsibility of the Contractor ---PAGE BREAK--- Standards and Specifications Section 700 Traffic Control Devices, Signs, and Street Lighting Page 7 to obtain clearance from the railroad company prior to doing any work within the boundaries of the railroad right-of-way. The minimum size of conduit to be used will be shown on the accepted plans or as required on the wire layout sheets. Conduits smaller then ¾ inch electrical trade size will not be used unless otherwise specified on the accepted plans, except that grounding jumpers at service points may be enclosed in ½ inch conduit. It will be the option of the Contractor to use, at his own expense, larger size conduit if desired. Where a larger size conduit is used, it will be used for the entire length of the run from outlet to outlet. No reducing couplings will be permitted in any conduit run. Conduits terminating in poles, cabinets or pedestal bases will extend a maximum of 4 inches and a minimum of 2 inches vertically above the foundation or will be sloped toward hand holes in poles or base opening where transformer bases are used. Conduit entering pull boxes will terminate a minimum of 1 inch and a maximum of 3 inches inside the box wall and 2 inches minimum or 4 inches maximum above the bottom and will be sloped to facilitate convenient pulling of the wires or cables. Conduit entering through the side of a pull box will be located near the sides and ends of the box in order to leave the major portion of the box clear. Conduits will enter freely through boxes for allowance of expansion and contraction. Conduit required to be terminated, stubbed and plugged will be shown on the plans as directed by the City Engineer. All conduit ends will be capped with standard conduit caps until the wiring is started. When caps are removed, the threaded ends will be provided with approved insulated metal ground bushings. The location of all ends of conduit for future electrical circuits in curbs or structures will be marked by a at least 3 inches high, cut into the face of a curb, gutter or wall directly above the conduit. These locations shall be shown on the as-built drawings in accordance with Section 106.2.2, As- Built Drawings, of these Standards and Specifications. Conduit bends, except for factory bends, will have a radius of not less than six times the inside diameter of the conduit. Where factory bends are not used, conduit will be bent without crimping or flattening using the longest radius practicable. Conduit entering controller cabinets will be packed with duct seal after wiring is installed to prevent the entrance of gases. Existing underground conduit to be incorporated into a new system will be cleaned with a mandrel and blown out with compressed air. Bends in all PVC conduit will be made to conform to all appropriate sections of the NEC or local codes governing bending radius and number of bends allowed, as applicable, for rigid conduit. At many locations on the City's streets, it is desirable to have conduit installed for future use. When PVC conduit is specified, a galvanized, l2-gauge sheet metal plate 12 inches square will be placed over each conduit end. Each end will be capped with PVC caps. Where a cap is indicated on the plans, a standard non-corrosive cap will be installed. Conduit terminating within a foundation will extend from 2 inches to 4 inches vertically above the foundation and installed in such a way that it will slope towards the hole opening. ---PAGE BREAK--- Standards and Specifications Section 700 Traffic Control Devices, Signs, and Street Lighting Page 8 All galvanized rigid conduit terminations within pull boxes will be fitted with insulating bushings to prevent chafing of wire on exposed edges. All conduit ends will be capped with standard conduit caps until wiring is started. When caps are removed, threaded ends will be protected with approved insulated metal ground bushings or insulated bushings if the conduit run is not extended from the threaded end and sealed by duct seal material. 702.8. Cable and Conductors 702.8.1. General Cable and conductors will conform to the applicable specifications of the IMSA and to those specifications shown on the accepted plans or as approved by the City Engineer. All wire furnished to or for the City will carry the label of the Underwriters’ Laboratories, Inc. This label will be present on each reel, coil or container of wire unless otherwise specifically approved by the City Engineer. Insulated conductors will be shipped in splice-free continuous in cartons or on new- bolted-type non-returnable reels plainly and indelibly marked with the name of the manufacturer, net weight, size (AWG) and length of the wire. Absolutely no splices of any kind will be permitted in the wire. A heavy covering of cardboard or burlap will be used to protect the wire and reels during shipment and handling. 702.8.2. Multiconductor Cable Where multiconductor cable is required, IMSA Specification 19.1 polyethylene-insulated, polyvinyl chloride-sheathed signal cable will apply, except that the conductors will be stranded. Conductor color coding will conform to Table II of IMSA Specification 19.1 for unpaired conductor cables. Color coding for tracers will run spiral and be impregnated into the conductor insulation. 702.8.3. Installation Methods – Wiring Wiring will conform to appropriate articles of the NEC. Wiring within cabinets, junction boxes, etc. will be neatly arranged and laced. Flax soap or other approved lubricants may be used for inserting conductors in conduit. No splices of cable will be permitted in the conduit of pull boxes, splice boxes, standards or pedestals. In all signal designs, separate conduits will be shown for separate low voltage and high voltage conductors on the plane. Signal conductors must be run in conduits separate from the low voltage detector lead-in or from the telephone interconnector. All loop detector wires will be pulled continuously for the full extent of the run from loop detectors to the cabinet with no splicing allowed in the runs. The contractor will perform his pulling operation in a manner so as to facilitate pulling the wire in continuous runs. ---PAGE BREAK--- Standards and Specifications Section 700 Traffic Control Devices, Signs, and Street Lighting Page 9 Required tags will be furnished and installed by the contractor at cabinet locations, at pull boxes and at terminating points, or as directed by the City Engineer. A permanent tag of fiber or PVC will be used for tagging all wires. Tags will be marked as indicated on the wire layout sheets and will indicate the direction of the run and pole number of other locations of termination points for the wire run. All spare wires will be ohmmed out, tagged and identified as spare with appropriate numbers as shown on the layout sheets. The ends of the spare wires will be pulled into the terminal compartment or cabinet. All wiring between the controller and the signal faces will be done with multiconductor cable. The individual conductor will be l4 gauge stranded copper wire. Separate multiconductor cables for each signal phase will be run around the intersection and marked with colored phasing tape at the controller and at each splice point in the pull boxes and pole bases. Color coding for individual conductors for controllers with pedestrian signals will conform to the specifications in Table 700-2: ---PAGE BREAK--- Standards and Specifications Section 700 Traffic Control Devices, Signs, and Street Lighting Page 10 TABLE 700-2. Color Coding Color Use Red Northbound Green Southbound Orange Eastbound Blue Westbound White Left Turn Yellow Pedestrian Brown Corner Black Feed 3 or 4 Conductor (for pedestrian buttons) Red A Black B White Common Green Spare 4 Conductor Loop Lead In Black-White Left Turn Red-Green Don’t Walk 5 Conductor Red Red or A Don’t Walk Orange Yellow or B Walk Green Green or A Walk Black B Don’t Walk White Neutral 7 Conductor Red Red or A Don’t Walk Orange Yellow or A Green Green or A Walk Black B Red or Don’t Walk White/Black B Yellow Blue B Green or Walk White Neutral Unused conductors will be folded back on the cable and securely taped. 702.8.4. Connections to Signalheads, Pushbuttons and Traffic Controllers All cable wires will be secured to screw-type terminals in the traffic signalheads, pedestrian pushbuttons and the traffic controller. The connectors will be the spade-tongue type and ---PAGE BREAK--- Standards and Specifications Section 700 Traffic Control Devices, Signs, and Street Lighting Page 11 affixed to the conductors using a tool designed specifically for the connection of the connectors to the conductors. 702.8.5. Wire Splicing Splices will only be made in pullboxes or pole bases. All splices made in pull boxes will be bundled together, and the bundle and all exposed conductors will be joined with a wire nut. All splices of individual conductors will be soldered and connected with appropriately sized wire nuts and taped in bundles with electrical tap covering the wire nuts to the point where the outer insulation of the multiconductor cable was cut. Loop detector and lead-in wire will run continuously from the loop detector to the controller terminals without splicing. The electrical service connections will be made by Xcel. The contractor will furnish two- conductor 6-gauge wire from the controller to the pull box, leaving 2 feet extra of wire in the pull box. The Contractor will be responsible for coordinating the service connection with Xcel. 702.8.6. Wire Bonding and Grounding Metallic cable sheaths, conduit, metal poles and pedestals will be bonded to form a continuous and effectively grounded system. Bonding jumpers will be #l0 AWG copper wire, or larger, as required. Grounding of conduit and neutral at the service point will be #8 AWG copper wire, or larger, as required. At each controller, a ground rod (electrode) will be installed. Each ground rod will be a one-piece solid rod of the copper-weld type, a minimum of ½ inch in diameter and 8 feet in length. This rod will be driven into the ground to a minimum depth of 7 feet below the surface. The ground wire will be completely spliced together at the aforementioned termination points and will tie into the neutral bar at the service facility, load center cabinet or control cabinet, to become a true and functioning common bond. 702.9. Traffic Signal Controllers 702.9.1. Actuated Controllers Lafayette traffic signal controllers shall be Eagle Signal EPAC 300, current version. Lafayette Controllers shall have a radio installed for remote access. Contact City Engineer for current standards. All signals on State highways will need CDOT permits. CDOT controllers are 170 type. The cabinet assembly shall include complete wiring for local intersection system operation, as indicated in the plans. Plans will be approved by the City Engineer prior to ordering parts. Plans shall be prepared by an engineer qualified in the area of signal systems design. 702.9.2. Cabinet Foundations Cabinet foundations will be completely poured in one operation and will be composed of concrete conforming to Section 600, Concrete Work, of these Standards and Specifications. The ground mount cabinet will be the bench-top type and will be as shown ---PAGE BREAK--- Standards and Specifications Section 700 Traffic Control Devices, Signs, and Street Lighting Page 12 on the accepted plans or as directed by the City Engineer. Anchor bolts will be installed using the supplied template with the cabinet on a foundation that has been poured level so that the cabinet will set flush with the foundation. As an alternative, a fiberglass cabinet base may be approved by the City Engineer. Foundations around controllers will be caulked both inside and outside the controller base to prevent water seepage. 702.9.3. Cabinet Locations Visual aesthetics should be considered in the location of signal controller cabinets. ---PAGE BREAK--- Standards and Specifications Section 1000 Site Work and Earthwork Page 1 Section 1000 Site Work and Earthwork 1000. SITE WORK AND 2 1001. 2 1001.1. LOCAL LAWS, ORDINANCES AND CODES 2 1001.2. PROTECTION OF PUBLIC IMPROVEMENTS 2 1001.2.1. Operation of Existing 2 1001.2.2. Interruption of . 2 1001.2.3. Equipment Operated on 3 1002. DEMOLITION AND REMOVAL OF STRUCTURES AND OBSTRUCTIONS 3 1002.1. BRIDGES, CULVERTS AND OTHER DRAINAGE 4 1002.2. 4 1002.3. PAVEMENTS, SIDEWALKS, CURBS, 4 1002.4. DISPOSAL 4 1003. SITE PREPARATION 5 1003.1. CLEARING 5 1003.2. GRADING AND EROSION 6 1003.3. DISPOSAL 7 1003.4. TOPSOIL 7 1004. EARTHWORK 7 1004.1. 7 1004.2. GRADING 9 1004.3. 9 1004.3.1. Excess Excavation 1004.3.2. Excavation Near Existing Structures and Utilities 1004.4. PROTECTION OF EXISTING STRUCTURES AND UTILITIES 1004.4.1. Relocation and Replacement of Existing Structures and Utilities 1004.5. EXCAVATED MATERIAL 1004.6. PROOF ROLLING 1004.7. EMBANKMENT FILL 1004.7.1. Structural Backfill 1004.7.2. Roadway Excavation, Backfill and Compaction 1005. RESTORATION AND CLEANUP ---PAGE BREAK--- Standards and Specifications Section 1000 Site Work and Earthwork Page 2 Section 1000 Site Work and Earthwork 1000. Site Work and Earthwork 1001. General All site work and excavation shall comply with the requirements of these Standards and Specifications and any special criteria established by the City. Special criteria may be established by the City Engineer at a pre-design meeting. Site work shall be completed as detailed on the accepted engineering plans. Site work shall consist of demolition and removal of structures and obstructions; clearing and grubbing; overlot grading; subgrade preparation; removal of topsoil; site preparation; excavation and embankment; excavation, trenching, bedding and backfill of pipelines and service lines; excess excavation; borrow; and restoration and cleanup. 1001.1. Local Laws, Ordinances and Codes The Contractor shall comply with all current federal, state and local laws, codes and ordinances pertaining to earthwork. The contractor shall obtain all necessary permits as required in Section 100, Scope, Title and General Conditions, of these Standards and Specifications and any permits required by this Section 1000, Site Work and Earthwork, prior to commencement of the work. The Contractor shall notify the City Engineer 24 hours before the start of the work or when work is to be resumed following a delay. 1001.2. Protection of Public Improvements The contractor will be held responsible for the protection of public improvements as stated in Section 103.1, Protection of Public and Utility Interests, of these Standards and Specifications. It will be the Contractor’s responsibility to replace all public improvements so damaged at his own expense. Street cuts are restricted according to Section 103.3 of these Standards and Specifications. 1001.2.1. Operation of Existing Valves The City Public Works Department will operate all existing valves, hydrants, blow-offs, and curb stops. No valve or other control device on any existing system will be operated for any purpose by the Contractor. 1001.2.2. Interruption of Services Before starting site work, the Contractor shall plan and coordinate for the disconnection or interruption of all services, such as water, wastewater, cable T.V., telephone, gas, electric power and traffic. Disconnection and/or interruptions shall be made in accordance with the regulations of the utility that controls the supply of the service. Whenever the flow of traffic is affected, a Traffic Control Plan shall be provided in accordance with Section 103.1.8, Traffic Control, Barricades, and Warning Signs, of these Standards and Specifications. ---PAGE BREAK--- Standards and Specifications Section 1000 Site Work and Earthwork Page 3 The City Public Works Department will provide a representative to be on site to observe and approve the Contractor’s disconnection or interruption of the water and wastewater services. Twenty-four hours prior to the interruption of service, the Contractor will notify all users whose service will be interrupted in order for them to make provisions for necessary water storage. No line in service will be shut down for more than a four-hour period at one time. Prior approval by the City Engineer is required for all shut-downs. 1001.2.3. Equipment Operated on Streets Tracked machines will only be used with proper street protection tires, wood) and only when a rubber tired machine isn’t adequate in size to accommodate the task at hand. 1002. Demolition and Removal of Structures and Obstructions The Contractor will remove, wholly or in part and satisfactorily dispose of all foundations, signs, structures, fences, old pavements, abandoned pipelines, traffic signal material and any other obstructions that are not designated or permitted to remain, except for utilities and for those items that are designated for removal by others. All salvageable material will be clearly marked by the City and shall be removed, without unnecessary damage, in sections or pieces that may be readily transported and will be stored in locations approved by the City Engineer. These materials may include, but shall not be limited to, manhole frames and covers, inlet grates, fence material, handrails, culverts, guardrail, walkway, roadway and parking appurtenances (traffic signals and attached hardware, including mast arms and spanwire) and irrigation systems and appurtenances. The Contractor will be required to replace any materials lost from improper storage methods or damaged by negligence. Removal of sign panels will include all work necessary to remove the panel and its attachment hardware from the existing installation. Concrete adhering to sign posts will be removed; pedestals and bases will be removed to 2 feet below the surrounding ground or subgrade. Where portions of structures are to be removed, the remaining parts will be prepared to fit new construction. The Work will be done in accordance with plan details and in such a manner that materials to be left in place will be protected from damage. All damage to portions of structures that are to remain in place will be repaired by the Contractor at his expense. Reinforcing steel, projecting from the remaining structure, will be cleaned and aligned to provide bond with new extension. Dowels are to be securely grouted with approved grout. Depressions resulting from the removal of structures, footings, and other obstructions, shall be filled and compacted with clean fill materials so as to eliminate hazards of cave-in or accumulation and ponding of water. Materials used in detour structures and supplied by the Contractor will be the property of the Contractor. After the detour is abandoned, he will completely remove the detour structure and will dispose of materials according to these Standards and Specifications. Immediately following demolition and removal of rubbish from the site, provided additional work is not required, the Contractor shall grade the entire contract area by filling, compacting, and leveling the site to existing adjacent grades. ---PAGE BREAK--- Standards and Specifications Section 1000 Site Work and Earthwork Page 4 1002.1. Bridges, Culverts and Other Drainage Structures Bridges, culverts, and other drainage structures in use by traffic will not be removed until a Traffic Control Plan has been approved by the City Engineer in accordance with Section 103.1.8, General Construction Conditions, of these Standards and Specifications. Unless otherwise directed, the substructures of existing structures will be removed down to 2 feet below natural stream bottom or ground surface. Where such portions of existing structures lie wholly or in part within the limits of a new structure, they will be removed as necessary to accommodate the construction of the proposed structure. Steel, precast concrete and wood bridges will be carefully dismantled without unnecessary damage. Steel members to be salvaged will be match-marked with waterproof paint. 1002.2. Pipe Unless otherwise provided, all pipe will be carefully removed and cleaned; every precaution will be taken to avoid breaking or damaging the pipe. Pipes to be re-laid will be removed and stored, when necessary, so that there will be no loss or damage before relaying. Where culverts or wastewater liness are to be left in place and plugged, the ends will be filled with concrete. Culvert and wastewater line ends are to be sufficiently filled to prevent future settlement of embankments. When removing manholes, catch basins and inlets, any live wastewater lines connected with these items will be properly reconnected and satisfactory bypass service will be maintained during such operations. 1002.3. Pavements, Sidewalks, Curbs, Etc. All concrete or asphalt that is to remain shall have a straight, true line with a vertical face. Concrete or asphalt may be cut with a cutting wheel or saw. If the Contractor cannot maintain a straight, true break line by other means, the City Engineer will order sawing. The sawing will be done carefully, and all damages to the concrete or asphalt to remain in place will be repaired by the Contractor at his expense. The minimum depth of saw cuts in concrete will be two inches. The Contractor will be responsible for the cost of removal and replacement of all overbreak as determined by the City Engineer. 1002.4. Disposal The Contractor will make all necessary arrangements for obtaining suitable disposal locations, and the cost involved will be included in the work. When disposing of Hazardous material, contractor will obtain certified receipt from landfill as to the proper disposal of the waste wastewater laden soil, asbestos, etc.). ---PAGE BREAK--- Standards and Specifications Section 1000 Site Work and Earthwork Page 5 1003. Site Preparation The Contractor shall complete all work necessary to satisfactorily prepare the site as shown on the accepted drawings and as specified herein. Following this preparation, the site shall be in such a condition as to easily continue with the next operation whether it be excavating, backfilling or any of the other operations that are part of the project. Site preparation includes clearing, grubbing, grading, tree and shrub removal, native grass stripping and removing and disposing of all debris within the limits of the project and such other areas as may be indicated on the plans or required by the work, except such objects as are designated to remain or are to be removed in accordance with other sections of these Standards and Specifications. This work will also include the preservation from injury or defacement of all vegetation and objects designated to remain. 1003.1. Clearing The City will establish construction lines and designate all trees, shrubs, plants and other things that are to remain. The Contractor will preserve all things designated to remain. Branches on trees or shrubs will be removed as directed. Branches of trees extending over the road bed will be trimmed to give a clear height of 20 feet above the road bed surface. All trimming will be done by skilled workmen and in accordance with good tree surgery practices. Hedges will be pulled or grubbed in such a manner as to assure complete and permanent removal. Sod not required to be removed will be thoroughly disked before construction of embankment. All surface objects and trees, stumps, roots and other protruding obstructions not designated to remain will be cleared and/or grubbed as required, except nonperishable solid objects, which will be a minimum of 2 feet below subgrade. Except in areas to be excavated, stump holes and other holes from which obstructions are removed will be backfilled with suitable material and compacted in accordance with these Standards and Specifications. The Contractor will strip areas where excavation or embankment is to be made. Stripping will include the removal of material such as brush, roots, sod, grass, residue of agricultural crops, sawdust, and other vegetable matter from the surface of the ground. Clearing shall be performed in a careful and orderly manner with due consideration and protection of adjoining property, the public and workmen. Any damage to streets, parking lots, utilities, plants, trees, buildings or structures on private property or to benchmarks and construction staking due to the negligence of the Contractor, shall be repaired and restored to the original condition by the Contractor at his expense. Those areas which are to be saved will be clearly staked or fenced off by the Contractor per the City’s instructions, and it will be the Contractor’s responsibility to ensure that these areas are not damaged during the construction process. Following completion of construction, ---PAGE BREAK--- Standards and Specifications Section 1000 Site Work and Earthwork Page 6 should any of these trees, shrubs or sod require replacement, it shall be done at the Contractor’s expense. 1003.2. Grading and Erosion Control A grading and erosion control permit is required for all overlot grading or earthwork. Each grading and erosion control permit application will include the following information, unless exempted in writing by the City Engineer: a. Plans showing: Vicinity map Property limits Accurate contours Detailed plans of all surface and subsurface drainage devices Finished contours Proposed erosion control measures b. Drainage report c. Geology and soils report d. NPDES permit from the state required for disturbance greater than 1 acre e. Details of revegetation Upon completion of the work where a grading permit is required, the Contractor shall provide the following information: a. An as-graded plan showing original ground surface elevations, as constructed ground surface elevations, lot drainage patterns and locations and elevations of all surface and subsurface drainage facilities. b. Statement certifying revegetation. All areas disturbed during grading operations shall have the final graded area hydroseeded or revegetated with native grasses in accordance with an approved landscape plan.. Seeding must be completed within 60 days of the grading completion and no longer than 180 days of the commencement of grading operations at the site. The Contractor shall insure that the dust-proofing requirements of Section 103.1.7, General Construction Conditions, of these Standards and Specifications are strictly adhered to for the duration of the project. Grading of filled and unfilled areas shall be to the lines and grades indicated on the accepted plans. Grading shall be performed in conjunction with all of the necessary clearing, grubbing, stripping, filling and compacting operations to the satisfaction of the City. Final grading shall be performed in such a manner as to provide proper drainage. In no case shall drainage from the project site be so altered or controlled as to result in damage, or the potential for damage, to adjacent property or to any portion of the work executed under the project from erosion or flooding. ---PAGE BREAK--- Standards and Specifications Section 1000 Site Work and Earthwork Page 7 1003.3. Disposal The Contractor will make all necessary arrangements for obtaining suitable disposal locations, and the cost involved will be included in the bid price. If disposal will be at other than established dump sites, the City Engineer may require the Contractor to furnish written permission from the property owner on whose property the materials and debris will be placed. Materials and debris will be disposed of in a manner acceptable to the City Engineer. When disposing of hazardous material, contractor will obtain certified receipt from landfill as to the proper disposal of the waste wastewater laden soil, asbestos, etc.). Burning will not be permitted without prior written approval of the City Engineer and the county health department. 1003.4. Topsoil The Contractor shall salvage within the project limits, or acquire when needed, loose friable loam reasonable free of admixtures of subsoil, refuse, stumps, roots, rocks, brush, weeds, heavy clay, toxic substances or other material which would be detrimental to the proper development of vegetative growth. Topsoil shall not be placed until the areas to be covered have been properly prepared and grading operations in the area have been completed. Topsoil shall be placed and spread at locations and to the thickness shown on the plans and shall be keyed to the underlying material. 1004. Earthwork This work shall consist of excavation, disposal, shaping or compaction of all material encountered within the limits of the project, including but not limited to excavation of ditches and channels, surface boulders, muck, rock, concrete foundations, slabs, stripping, etc. Excavation will be performed to the line and grade and typical cross- sections indicated on accepted plans or as required by the City Engineer. All earthwork is to be done to OSHA and other applicable standards. Excavation, dewatering, sheeting, and bracing shall be carried out in such a manner as to eliminate any possibility of undermining or disturbing the foundation of any existing structures or any work previously completed. 1004.1. Definitions Bedding material, heavy structures – Material installed under concrete pipe, riprap, low flow channel or any other place considered necessary by the City Engineer. The thickness of this material will be as shown on the accepted plans and will normally be 6 inches under structures and 3 inches under the bell of any pipe. Bedding material shall meet the gradation of CDOT No. 67 Coarse Aggregate as specified in Section 703.02 of the CDOT Standard Specifications for Road and Bridge Construction (1999). Bedding material, pipelines – Material under and around pipelines shall be either well- graded sand or squeegee-graded. Bedding material for water lines shall be clean, well- graded sand or squeegee sand and shall conform to the following limits when tested by means of laboratory sieve: ---PAGE BREAK--- Standards and Specifications Section 1000 Site Work and Earthwork Page 8 TABLE 1000-1. LIMITS FOR WELL-GRADED SAND Sieve Size Total % Passing by Weight ⅜ inch 100 No. 4 70 – 100 No. 8 36 – 93 No. 16 20 – 80 No. 30 8 – 65 No. 50 2 – 30 No. 100 1 – 10 No. 200 0 – 3 Squeegee Sand ⅜ inch 100 No. 200 0 - 5 Bedding material for all other pipe (except as noted below) shall be as defined in this section. Borrow – Backfill or embankment material that must be acquired from designated borrow areas to make up the deficient areas that cannot be completed from excavation within work limits. All sources of borrow material must be approved by the City Engineer. Embankment fill – Earthwork consisting of embankments, including preparation of the area upon which they are to be placed, dikes within or outside right-of-way, placing and compacting of approved material within areas where unsuitable materials have been removed, and placing and compacting of embankment materials in holes, pits and other depressions to lines and grades shown on the accepted plans. Only suitable materials shall be used in construction of embankments and backfills. Proof rolling – The application of test loads over a subgrade surface by means of a heavy pneumatic-tired vehicle to locate weak areas in subgrade. See Section 1004.6, Proof Rolling, for specifications. Rock excavation – Igneous, metamorphic or sedimentary rock formations that cannot be excavated with a D-9 tractor, in good repair with a single hydraulic ripper, or trench excavation that cannot be completed with a ¾ yard backhoe with rock teeth. Stabilization material – Material to be placed in areas of over-excavation of unsuitable in situ material, or in areas of high water table to stabilize the in situ material. Stabilization material shall meet the gradation of No. 4 Coarse Aggregate as specified in Section 703.02 of the CDOT Standard Specifications for Road and Bridge Construction. ---PAGE BREAK--- Standards and Specifications Section 1000 Site Work and Earthwork Page 9 Structure backfill – Earthen material installed around and over any structure as illustrated on the accepted plans. Imported structure backfill (Class I) shall meet the general gradation of “Class 1 Structure Backfill Material” as specified in Section 703.08 of the CDOT Standard Specifications for Road and Bridge Design. On-site Class 2 structure backfill shall also meet the requirements of Section 703.08 of the CDOT specifications. Structure excavation – Excavation of any and all materials over an area extending 3 feet out from the outermost bottom edge bottom edge of a proposed structure, up to existing grade or top of proposed grade (whichever comes first) at a one-to-one slope. Rock formations within this area that can be removed by ripping with a D-9 tractor (in good repair with a single hydraulic ripper) shall be considered structure excavation. Suitable material – Any earthen material consisting of on-site or similar non-organic sands, gravels, clays, silts and mixtures thereof with a maximum size of 6 inches. Bedrock that breaks down to specified soil types and sizes during excavation hauling and placement may be considered as suitable material Unclassified material – Any earthen material containing vegetable or organic silt, topsoil, frozen materials, trees, stumps, certain manmade deposits, or industrial waste, sludge or landfill, oversize rocks or other undesirable materials. Unclassified excavation – Any and all earthen materials encountered, including rocks and boulders, during construction. Rock formations that can be removed by ripping with a D-9 tractor in good repair with a single hydraulic ripper are considered to be unclassified excavation. 1004.2. Grading Tolerances All earthwork shall be carried out in such a manner that final grades, after excavation, compaction of backfill, placement of riprap and construction of channel lining, etc., shall conform to those illustrated by design cross-sections. The final earthwork shall be considered acceptable, provided all final grade elevations do not vary from the designed elevations by more than the following: a. 0.1 foot within main drainage channel bottom limits b. 0.3 foot at the top of any embankment where a cut side slope intersects the existing grade c. 0.5 foot in all portions of the site not included in items a or b above d. In addition to the above tolerances, positive surface drainage shall be provided on the entire site so that no depressions or ponds are formed, regardless of depth. It shall be the Contractor’s responsibility to insure that all portions of the site drain as shown on the accepted plans. 1004.3. Excavation All excavated areas will be graded in a manner that will permit adequate drainage, will not disturb material outside the limits of slopes and will be within the tolerances noted in Section 1004.2, Grading Tolerances, of these Standards and Specifications. When ---PAGE BREAK--- Standards and Specifications Section 1000 Site Work and Earthwork Page 10 practical, all suitable material removed from the excavation will be used in the formation of embankments, for backfilling and for other purposes. Materials that are considered unsuitable material (including rock) or surplus by the City Engineer shall be disposed of by the Contractor at his expense, in accordance with Section 1003.3, Disposal, of these Standards and Specifications. All water pumped or drained from the work shall be disposed of in a manner satisfactory to the City Engineer, without undue interference with other work or damage to pavements, other surfaces or property. Contractor shall obtain a State of Colorado dewatering permit as applicable 50,000 gallons per day of pumping). All disinfected water shall be dechlorinated prior to release. 1004.3.1. Excess Excavation If, in the opinion of the City Engineer, the material at or below the depth to which excavation for structures would normally be carried is unsuitable for the required installation, it shall be removed to such widths and depths as directed by the City Engineer and shall be replaced with stabilization material. Where the bottom of the excavation, by error of the Contractor, has been taken to a depth greater than the depth specified, as shown on the accepted plans or directed by the City Engineer, said condition shall be corrected by refilling to the proper grade with structural backfill. Should this backfill for over-excavation occur in areas of high groundwater, then the backfill material shall be stabilization material. All measures taken to rectify conditions caused by over-excavation shall be approved by the City Engineer, and the cost resulting from such measures shall be borne by the Contractor. If, through failure or neglect of the Contractor to conduct the excavation work in a proper manner, the surface of the subgrade is in an unsuitable condition for proceeding with construction, the Contractor shall, at his own expense, remove the unstable material and replace it with recycled concrete, structural backfill, or other approved material so that the condition of the subgrade meets with the approval of the City Engineer before any work is placed thereon. Failure of the Contractor to control surface or groundwater adequately, or improper conduct of work, as determined by the City Engineer, shall be grounds for requiring removal and replacement of unsuitable subgrade without additional compensation. 1004.3.2. Excavation Near Existing Structures and Utilities The Contractor’s attention is directed to the fact that underground utilities may exist within or immediately adjacent to the areas of proposed construction. Where possible, these utilities are indicated on the accepted plans; however, all of the services may not have been shown on the accepted plans, and the completeness and accuracy of the information presented is unverified and without guarantee. This information is supplied for the purpose of providing the Contractor with an indication as to the approximate ---PAGE BREAK--- Standards and Specifications Section 1000 Site Work and Earthwork Page 11 locations of utilities at the work areas so that he will be made aware of probable obstructions and the extent to which construction may be affected by these. All utility lines shall be located on the ground with location equipment well ahead of the work at all times. All such locations shall be plainly marked by coded paint symbols on pavement or by marked stakes in the ground. Contractor shall call UNCC (1-800-922- 1987) at least 48 hours prior to any excavation. 1004.4. Protection of Existing Structures and Utilities All infrustructure to include but not be limited to existing poles, pipes, wires, fences, curbs, property line markers, and other structures which, in the opinion of the City Engineer, must be preserved in place without being temporarily or permanently relocated, shall be carefully supported and protected from damage by the Contractor. In case of damage, the Contractor shall notify the property owner so that proper steps may be taken to repair any and all damage done. When the property owners do not wish to make the repairs themselves, all damage shall be repaired by the Contractor; or, if not done by him, the City may have the repairs made at the expense of the Contractor. All utility services shall be supported by suitable means so that services do not fail during construction or when tamping and settling occur. 1004.4.1. Relocation and Replacement of Existing Structures and Utilities If, in the course of construction, the Contractor encounters utility services and/or structures of any kind not indicated on the plans, or otherwise provided for, which encroach upon or are encountered near and substantially parallel to the edge of the excavation, he shall cease work and contact the City Engineer. Conflicting utilities shall be relocated, removed (later to be restored), replaced, or the new utility adjusted. The contractor shall be issued a change order for extra work involving other utilities or substantial design changes. When fences interfere with the Contractor’s operations, he may remove and, unless otherwise specified, later restore them to a condition at least as good as that in which they were found immediately before the work was begun, all without additional compensation. The restoration of fences shall be done as as possible and not left until the end of the construction period. 1004.5. Excavated Material Excavated material shall be placed so as to minimize the inconvenience to occupants traveling on streets and driveways or adjoining properties. Excavated material shall not be deposited on private property unless written consent of the property owner(s) has been filed with the City Engineer. ---PAGE BREAK--- Standards and Specifications Section 1000 Site Work and Earthwork Page 12 It is expressly understood that no excavated materials shall be removed from the site of the work or disposed of by the Contractor except as directed or approved by the City Engineer or as noted below. Suitable excavated material will be used as backfill, fill for embankments or other parts of the work in accordance with the appropriate sections of these Standards and Specifications. Disposal of surplus material shall be in accordance with Sections 1002.4 and 1003.3 of these Standards and Specifications. 1004.6. Proof Rolling Proof rolling will be required to determine whether certain areas of subgrade meet compaction requirements. Where required by the City Engineer, proof rolling shall be carried out as designated with a loaded 2,000 gallon single axle water truck. Tires shall be inflated to a minimum of 70 pounds per square inch and a maximum pressure of 90 pounds per square inch. No separate payment shall be made for proof rolling operations. Areas of subgrade already worked, but show signs of movement when proof rolled,, shall be ripped, scarified, moisture adjusted if necessary, and at the Contractor’s expense. The passing of a proof roll is only an indication of potentially adequate construction. It does not relieve the contractor of any responsibility or void any warrantee. 1004.7. Embankment Fill Earth fill shall be constructed in accordance with this section, including placing and compacting of all embankment material and all related work as required to ensure proper bond of materials with previously placed embankment. No material shall be placed in any section of embankment until the foundation for that section has been cleared, stripped and dewatered and compacted in accordance with these Standards and Specifications. The suitability of each part of the foundation for placing embankment material thereon and of all materials for use in the embankment construction will be as determined by the City Engineer or his designated representative (Soils Engineer). All materials shall be placed and compacted in approximately horizontal layers of the specified thickness. The thickness of each layer shall not exceed 6 inches before compacting. After subgrade has satisfactorily been prepared, the fill material shall be placed and compacted thereon and built up in successive layers until the required elevation is reached. Fill shall be placed within the lines and grades shown on the accepted plans or as directed by the City Engineer. No fill shall be placed on frozen surfaces nor shall the fill material contain snow, ice, or other frozen materials. ---PAGE BREAK--- Standards and Specifications Section 1000 Site Work and Earthwork Page 13 Fill for embankment shall be a homogenous mixture of stockpiled suitable material. The characteristics of the material shall be in accordance with that of suitable material as defined in Section 1004.1, Definitions, of these Standards and Specifications. The filling operation shall begin in the deepest part of the area to be filled and fill shall be brought up in essentially level lifts. Fill shall be placed in layers by an approved method. The entire surface of the work shall be maintained free from ruts and in a condition that will permit construction equipment to travel over any section readily. The lifts may be discontinued, providing that the slopes of the bonding surfaces of adjoining portions of embankment shall not be steeper than 10:1 (horizontal to vertical). Previously placed material shall be moistened in such a manner and to such depths as will ensure a satisfactory bonding surface with a new material. The Contractor shall maintain the embankment in a manner satisfactory to the City Engineer until final acceptance of all work has been given by the City. Previously placed or new materials shall be moistened by sprinkling, if required, to insure proper bond and compaction. No compacting shall be done when the material is too wet, causing yielding. If the compacted surface of the fill layer is determined to be too smooth to provide an adequate bond with the succeeding layer, the surface shall be loosened by harrowing or by some other approved method before placement of the succeeding layer. Excavated materials that are too dry for immediate compaction, but are otherwise suitable for embankment, shall be wet to the proper moisture content before placing them in the embankment. No additional payment will be made for drying materials for use in the embankment. The moisture content of the embankment prior to and during compaction shall be distributed uniformly throughout each layer of material. The placement moisture content for all materials shall be as noted below. The Contractor will be responsible for insuring that compaction tests will be made when the Contractor has determined that he has properly compacted the embankment. There shall be one test for each 200 cubic yards of material placed. All embankment fill shall be compacted to a minimum of 90% maximum dry density based upon a site specific standard proctor, ASTM D-698. Moisture shall be within 2% of optimum. Fill under structures or roads shall be compacted to 95% of maximum dry density at ± 2% moisture. Where pavement or foundation design requires moisture conditioning, the site specific procedures will be applied. If at any time the City Engineer judges that the degree of compaction being obtained is insufficient, he may halt operations and order that compaction tests be taken at his direction. Areas found deficient in degree of compaction shall be recompacted and regraded if necessary. ---PAGE BREAK--- Standards and Specifications Section 1000 Site Work and Earthwork Page 14 1004.7.1. Structural Backfill Structural backfill material shall be used to backfill behind reinforced concrete structures as illustrated on the accepted plans. Structural backfill shall comply with material as described in Section 1004.1, Definitions, of these Standards and Specifications. In addition, this material shall have a liquid limit not exceeding 35 and a plasticity index of not over 15 when determined in conformity with AASHTO T 89 and T 90. Areas adjacent to structures and other areas inaccessible to mobile compaction equipment shall be compacted with suitable power-drive hand tampers or other acceptable devices. Compaction by the latter method shall be done in 6 inch layers, unless otherwise directed by the City Engineer. Backfilling shall consist of placing materials in horizontal, uniform layers brought up uniformly on all sides of the structure. The thickness of each layer of backfill shall not exceed 6 inches before compacting to the required density. Backfill material shall not be deposited against the back of concrete abutments, concrete retaining walls, or the outside of cast-in-place concrete structures until the concrete has developed a strength of not less than 2,500 pounds per square inch in compression. Backfill placed within 2 feet of any structure shall be brought up evenly on all sides to avoid unequal lateral pressures. Compaction equipment or methods that produce horizontal or vertical earth pressures that may cause excessive displacement or may damage structures, shall not be used. Unless otherwise indicated on the accepted plans or directed by the City Engineer, all sheeting and bracing used in making structure excavation shall be removed by the Contractor prior to backfilling. Excessive use of water during backfilling operations will not be permitted. Backfill will be or of optimal moisture as determined by the soil investigation. The passing of compaction testing is only an indication of potentially adequate construction. It does not relieve the contractor of any responsibility or void any warrantee. In the event that sufficient satisfactory backfill material is not available on the site, the City Engineer shall direct the Contractor to import Class 1 structure materials as defined in Section 1004.1, Definitions, of these Standards and Specifications. The Contractor shall not be required to excavate below the depths of excavation indicated on the accepted plans to provide structural backfill material. However, to the extent that acceptable material is available within the excavation limits, the Contractor will be required to excavate, transport, and compact the material without compensation beyond that which may be included for “Unclassified Excavation Used as Structural Backfill” or as may be allowed for in the bid documents. ---PAGE BREAK--- Standards and Specifications Section 1000 Site Work and Earthwork Page 15 Where pipe is connected to a structure being backfilled, the bedding and backfilling procedure shall conform to the requirements for the particular type of pipe being installed. The Contractor shall apply the proper compaction effort and moisture control throughout the backfilling process. The Contractor shall be responsible for insuring that compaction tests are made of the fill when the Contractor has determined that he has properly compacted the structural backfill. Testing shall be completed in accordance with for each 200 cx of material or part thereof placed. If at any time the City Engineer judges that the degree of compaction being obtained is insufficient, he may halt operations and order that compaction tests be taken at his direction. Areas found deficient in degree of compaction shall be recompacted and regraded if necessary. Failed compactions tests, when ordered by the City Engineer, shall be paid for by the Contractor. Additional tests ordered by the City Engineer that meet requirements of these Standards and Specifications will be paid for by the City. 1004.7.2. Roadway Excavation, Backfill and Compaction Roadway excavation shall be in accordance with unclassified excavation as defined in Section 1004.1, Definitions, of these Standards and Specifications, except for areas of rock excavation as defined in the same section. The material and execution for the roadway backfill shall conform to Section 1004.7, Embankment Fill, of these Standards and Specifications. All roadway backfill shall be compacted to at least 95% of maximum density at optimum moisture content in accordance with ASTM Specification Designation D-698 (Standard Proctor). Water shall be applied uniformly during compaction to control moisture content. The moisture content will be maintained with ± 2% of optimum moisture unless special conditions are encountered and other procedures are specified by the soils engineer. Prior to placement and compaction of roadway fill, all existing rubble and organic material shall be removed down to suitable existing material. The existing material shall then be scarified and roadway fill placed in accordance with Section 1004.7, Embankment Fill, of these Standards and Specifications. 1005. Restoration and Cleanup At all times during construction, the Contractor shall maintain the site, partially finished structures, material stockpiles and other like areas in a reasonable state of order and cleanliness. The surface grade and condition of all unsurfaced areas shall be restored to the grade and condition immediately prior to construction. The Contractor will restore or replace all sod, trees, shrubbery, sprinkler systems, fences and any other items to a condition equal to that before the work began and to the satisfaction of the City Engineer. All grassed ---PAGE BREAK--- Standards and Specifications Section 1000 Site Work and Earthwork Page 16 areas shall be reseeded or resodded, and the Contractor shall be responsible for caring for the grass until its growth is established. All roadway surfacing, curbing, sidewalks and gutters will be restored or replaced to a condition equal to that before the work began and to the satisfaction of the City Engineer. All roadway surfacing between the vertical surface cuts on each side of the excavation shall be removed and replaced with base course material and/or hot mix bituminous or concrete surfacing. Asphalt will be in place by the end of work every Friday. If hot mix is not available, cold mix may be placed and later removed for a proper hot mix patch. All temporary work is at the contractor’s expense. Pavement repair will be completed as described in Section 103.3, Pavement Cuts, of these Standards and Specifications. Before final acceptance, the project area, material pits and ground occupied by the Contractor in connection with the work shall be cleaned of all rubbish, excess materials, temporary structures and equipment; and all parts of the work shall be left in an acceptable condition to the satisfaction of the City Engineer. In the event of the Contractor’s failure to perform the above work, the work may be performed by the City at the expense of the Contractor. ---PAGE BREAK--- Standards and Specifications Section 1200 Water Supply Facilities Design Criteria Page 1 Section 1200 Water Supply Facilities Design Criteria 1200. DESIGN CRITERIA 3 1200.1. DESIGN FLOW 3 1200.2. OPERATING PRESSURE 3 1200.3. FIRE HYDRANT 3 1200.3.1. Single-Family 3 1200.3.2. Commercial, Multi-Family, Industrial, Business 4 1200.4. FIRE LINE TO NON-RESIDENTIAL AREA 4 1200.5. DISTRIBUTION SYSTEM 4 1200.6. VALVE 4 1200.7. AIR AND VACUUM RELIEF 5 1200.8. BLOW-OFF VALVES 5 1200.9. HYDRAULIC 5 1200.10. LOCATION 5 1200.11. PIPE DEFLECTION 5 1200.12. MINIMUM 5 1200.13. SERVICE 6 1200.14. PIPE 6 1200.15. PIPE MATERIALS 6 1200.15.1. Pipe 6 1200.15.2. Polyethylene Wrap for Ductile Iron 6 1200.15.3. Fittings 7 1200.15.4. Gate Valves 7 1200.15.5. Butterfly 7 1200.15.6. Pressure-Reducing Valves 7 1200.15.7. Fire 8 1200.15.8. Valve 8 1200.15.9. Air and Vacuum Relief 9 1200.15.10. Blow-off 9 1200.15.11. Vaults 9 1200.15.12. 9 1200.15.13. Manhole Base Slabs and Base 9 1200.15.14. Sump Pits for Vaults and Manholes 9 1200.15.15. Vent Pipes 1200.15.16. Corrosion Protection Systems 1200.15.17. Tracer Wire 1200.15.18. Bedding Materials 1200.15.19. Concrete 1200.15.20. Plastic Liner Pipe (Sliplining) 1200.15.21. Steel Casings for Bores 1200.16. TAPS 1200.16.1. Service and Fire Lines 1200.17. METERS 1200.17.1. Size of Meter 1200.17.2. Small Water Meters 1200.17.3. Large Meters (3 in and larger) 1200.17.4. Outside Meter Settings 1200.17.5. Inside Meter Setting and Remote Readers 1200.17.6. Meter Bypass Line 1200.17.7. Backflow Prevention Devices 1200.17.8. Valves for Use with Meters 1200.17.9. Meter Yokes (Line Setters) ---PAGE BREAK--- Standards and Specifications Section 1200 Water Supply Facilities Design Criteria Page 2 1200.17.10. Valve and Meter Supports 1200.17.11. Residential Meter Pits and Covers 1200.17.12. Corporation Stops 1200.17.13. Curb Stops 1200.17.14. Curb Stop Service Boxes 1200.18. MODIFICATIONS TO EXISTING SYSTEM ---PAGE BREAK--- Standards and Specifications Section 1200 Water Supply Facilities Design Criteria Page 3 Section 1200 Water Supply Facilities Design Criteria 1200. Design Criteria All water distribution systems will comply with the requirements of the Standards and Specifications for water main and service line construction and may include special criteria established by the City for the overall hydraulics of the water utility system. Special criteria shall be outlined at pre-design meetings. 1200.1. Design Flow Requirements The design of the water distribution system will be based on the following unless more detailed data is available: Table 1200-1. Unit Water Demands for Future Land Use Land Type Maximum Day Demand Max. Hr. / Max. Day Single Family Residential 1100 gpd/unit 2.5 Multi-Family Residential 550 gpd/unit 2.5 Retail 3,500 gpd/Acre 2.5 Industrial 1,500 gpd/Acre 2.5 Park 4,500 gpd/Acre 5.0 Fire flows may be calculated from more than one hydrant, providing the hydrants used are directly accessible to all possible fire locations in the area served. Minimum fire flow shall be as noted below: Single Hydrant 750 GPM Residential 1,500 GPM Industrial/Commercial 3,500 GPM 1200.2. Operating Pressure Requirements Distribution systems will be designed to maintain a 20 psi residual pressure during required fire flow and a 40 psi residential residual pressure during peak residential flows. 1200.3. Fire Hydrant Spacing In residential areas, fire hydrants will be spaced per City code Section 26-19-10 and the Fire Marshall. A hydrant will be placed in the end of each cul-de-sac over 300 feet in length and at all dead ends. Fire hydrant locations and spacing must be reviewed and accepted by the Fire Department. 1200.3.1. Single-Family Residential There shall be a fire hydrant within 250 feet of any single-family residential building and the maximum spacing is 500 feet. ---PAGE BREAK--- Standards and Specifications Section 1200 Water Supply Facilities Design Criteria Page 4 1200.3.2. Commercial, Multi-Family, Industrial, Business There shall be a fire hydrant within 175 feet of any structure. Maximum hydrant spacing is 350 feet. 1200.4. Fire Line to Non-Residential Area The owner will maintain all fire lines between the valve on the City water main and the structure. Valves on newly-constructed fire lines will be located on the tee at the main line. Fire lines are to be used exclusively for fire protection. Domestic water taps and/or irrigation taps will be not allowed on the fire line unless written approval to do so is given by the City Engineer. 1200.5. Distribution System Layout A conceptual utility layout will be provided at the sketch plan level of review to determine if any oversizing is required for conformance with the City of Lafayette water master plan. For developments with a build-out area greater than 20 acres, hydraulic modeling may be required. Lateral lines will normally be 8-inch diameter pipe. When approved by the City Engineer, 6-inch diameter lines may be installed in cul-de-sacs less than 300 feet long with a fire hydrant at the end. Dead ends will be minimized by looping whenever possible. Lines at ends of long cul-de- sacs shall be looped along lot lines to adjacent streets Mains and laterals shall be extended to the boundaries of Filings and completely across the frontage of individual lots. Mains may be oversized at the request of the City Engineer to meet City Master Plan guidelines. 1200.6. Valve Spacing Valves will be placed with a maximum spacing of 600 feet in all distribution mains and lateral lines. Where City blocks exceed 600 feet in length, an intermediate valve shall be installed. Valves shall be provided so that no more than two hydrants are out of service when a section of main is shut off. Valves will also be placed at each fire hydrant and permanent blow-off. Four-way and three-way street intersections shall require three and two valves respectively. This also applies to new tees and connections to the existing system (wet taps). Valves shall also be placed at each end of a line running through an easement on private property, on each side of a major creek or channel crossing and on each side of a distribution line that provides service to a hospital, school or large industrial user. ---PAGE BREAK--- Standards and Specifications Section 1200 Water Supply Facilities Design Criteria Page 5 1200.7. Air and Vacuum Relief Valves Combination air and vacuum relief valves shall be installed at each high point in all transmission mains 18 inches and larger and at high points of lateral lines as may be required by the City Engineer. Air and vacuum relief valves shall be installed in precast manholes or vaults fitted with air vents open to the atmosphere and in accordance with Standard Drawing No. 200-1. 1200.8. Blow-off Valves Provisions shall be included in the design to allow for the flushing of distribution mains and lateral lines at any low point in the system, or at any point noted on the accepted plans. The blow-off assembly shall be installed perpendicular to and on the downhill side of the main or line and shall drain to the nearest gutter line or drainage channel. The blow-off assembly standpipe must have a threaded end to accept a fire hose coupling. The top of the standpipe shall be 8 inches below grade in accordance with Standard Drawing No. 200-2. 1200.9. Hydraulic Design All pipes will be designed to have a maximum velocity of 5 feet per second for peak day non-fire flows. 1200.10. Location (Typical) Water mains will typically be located 10 feet north or west of the centerline of the street unless otherwise approved by the City Engineer. At street intersections, valves will be located 5 feet from fittings. Fire hydrant gate valves will be placed at the main with a swivel tee. All fire hydrants will have a restrained connection directly to the tee off the main (see Standard Drawing No.200-3). In all instances, the water mains will extend to the boundary line of the property or subdivision served. A main serving one lot will extend the entire way across the frontage for that lot. Mains serving a subdivision will extend to the boundary lines or to the outside of paved areas. 1200.11. Pipe Deflection Changes in direction of PVC pipe will require bends in all instances. Deflection of PVC pipe is not allowed. Ductile iron pipe joints may be deflected according to manufacturer’s recommendations only. 1200.12. Minimum Depth All pipe will be installed with a minimum of 4 feet 6 inches of cover from finished grade of street to the top of the pipe barrel. ---PAGE BREAK--- Standards and Specifications Section 1200 Water Supply Facilities Design Criteria Page 6 1200.13. Service Connections Service connections for ¾ through 2 inch services shall be double strapped bronze saddles. Ball type corporation stops are required. 3 inch and larger services shall be tee fittings with a valve and valve box. 1200.14. Pipe Clearance Water lines shall have a minimum clearance of 18 inches from all other utilities. 1200.15. Pipe Materials 1200.15.1. Pipe All pipe for water main construction will be either C905, C900 or C909 PVC pipe, at the discretion of the City Engineer. PVC Pipe: All PVC pressure pipe in sizes up through 12 inches in diameter shall be in conformance with AWWA C-900 and have a minimum working pressure of 200 psi (DR- 14). PVC pressure pipe in sizes 14 inches through 36 inches in diameter shall be in conformance with AWWA C905-88 and have a minimum working pressure of 165 psi (DR-25). PVC pressure pipe 14 inches through 36 inches in diameter and having operating pressures in excess of 125 psi, or when required by the City Engineer, shall have a minimum working pressure of 235 psi (DR-18). Installation of PVC pipe shall be in conformance with the manufacturer’s recommendations and these Standards and Specifications. A No. 14 AWG stranded copper wire shall be attached to all PVC pipe for the purpose of future location in accordance with Standard Drawing No. 200-4. Ductile iron pipe (DIP) will only be used with special permission of the City Engineer. All ductile iron pipe will be in conformance with AWWA C151. Pipe class shall be appropriate for the pressure anticipated. Joints will be mechanical or push-on, in conformance with AWWA C111. Ductile iron pipe will have a standard cement mortar lining in conformance with AWWA C104 and a bituminous outside coating approximately 1 mil thick. Each pipe will be marked with the weight, class designation and size. Cathodic protection, to include test station and donator anodes, will be added. Joints will be double bonded from pipe to pipe. 1200.15.2. Polyethylene Wrap for Ductile Iron Pipe All ductile iron pipe shall be wrapped with 8 mil polyethylene. ---PAGE BREAK--- Standards and Specifications Section 1200 Water Supply Facilities Design Criteria Page 7 1200.15.3. Fittings Ductile iron fittings will be in conformance with AWWA C110. Class designation will be compatible with the pipe class designated for the project. Joints will be either mechanical or push-on type conforming to the requirements of AWWA C111. A standard thickness cement mortar lining will be applied in conformance with AWWA C104. All ductile iron fittings installed on PVC pipe will be fusion-bonded epoxy coatings conforming to the requirements of AWWA C116. PVC fittings will not be allowed. 1200.15.4. Gate Valves Gate valves in sizes 4 inches to 12 inches will be of the iron body, non-rising stem, resilient-seated type meeting AWWA standard C509. All valves shall be American made and locally available. An anti-friction washer will be placed above the thrust collar to further minimize operating torque. Structural design of the valve will be such that if excessive torque is applied to the stem, failure of the pressure retaining parts will not occur. Stem failure under such conditions will occur externally at such a point as to enable the stem to be safely turned by use of a pipe wrench or other such readily available tool after exposure of the valve. The stem will then be replaceable through removal of the two-bolt stuffing box. Coatings will be equal to or exceed AWWA C550. 1200.15.5. Butterfly Valves All valves having a nominal diameter greater than 12 inches will be geared butterfly valves designed for direct burial and will conform to AWWA specification C504, Class 150-B. Valves will be of the tight closing rubber seat type with rubber seats bonded to the valve body. No metal-to-metal sealing surfaces will be permitted. Valves will be bubble tight at 150 psi rated pressure with flow in either direction. Valve discs will rotate 90 degrees from the full open position to the tight shut position. Butterfly valves used with Class 200 PVC shall include a standard pipe spacer to allow for unobstructed movement of the valve. Coatings will conform AWWA C550. Valve bearings will be sleeve-type corrosion-resistant and self-lubricating with the load not to exceed 2500 psi. Valve operators will be the traveling nut type designed to withstand 300 foot pounds of input torque at full open or closed positions without damage to the valve or operator; will be fully gasketed, grease packed, and designed to withstand submersion in water to 10 psi; and will close with a clockwise rotation of a 2 inch square AWWA nut. 1200.15.6. Pressure-Reducing Valves Valves shall be a Pressure Reducing Valve as manufactured by Clay-Val Co., with model to be determined by the City of Lafayette. ---PAGE BREAK--- Standards and Specifications Section 1200 Water Supply Facilities Design Criteria Page 8 All pressure reducing valves shall be 250 lb. class. Distribution main and lateral line pressure reducing valves shall be installed in a vault. Piping must be ductile iron through the vault walls extending 3 feet past the vault walls and shall be as shown on Standard Drawings No. 200-5 and 200-6. 1200.15.7. Fire Hydrants Hydrants shall be the Manufacturer’s latest design, manufactured and tested in compliance with the latest edition of AWWA C-502, Standard for Dry Barrel Fire Hydrants. Acceptable fire hydrants are Mueller Super Centurion 250, A423 or Waterous Pacer 100 WB-67. Hydrants shall include bronzed bushed shoe providing bronze to bronze seating for the main valve, complete with O-rings for sealing, and a bronze shaft coupling. Hydrants shall be traffic type with replaceable breakable units immediately above the ground line for minimizing repairs due to traffic damage. The buried portion of the hydrant shall be given a bituminous coating in accordance with AWWA C-106. All ferrous metal parts shall be coated in accordance with AWWA C- 500. The bonnet and nozzle cap shall be given one shop coat of red color heavy duty alkyd enamel paint. Hydrants will have a 5¼ inch main valve opening with a 6 inch mechanical joint end. Each hydrant will be equipped with a 4½ inch pumper nozzle and with two 2½ inch hose nozzles with National Standard threads. Hydrant valve will open counterclockwise from a standard operating nut. Hydrants will be designed for 5 feet pipe bury and will not be buried below the first flange. Refer to Standard Drawing No. 200-3. The hydrant manufacturer shall furnish a sworn affidavit stating that all hydrants furnished comply with all applicable provisions of AWWA C-502 standards as modified or supplemented herein. A copy of the certification shall be forwarded to the City Engineer. 1200.15.8. Valve Boxes All buried valves will be provided with a valve box. Valve boxes will be gray cast iron, ASTM A48 Class 20A, three-piece adjustable screw boxes with a round base and a 5¼ inch screw-type shaft suitable for depth of cover adjustments as required. Box lids will be marked with the word Water. All valves which are set at greater than normal depth will have an extension stem provided and installed with the valve box so that the valve may be operated with a standard 7-foot valve key. Valve boxes and final grade will be accepted by the City Engineer only when the final grade is completed. ---PAGE BREAK--- Standards and Specifications Section 1200 Water Supply Facilities Design Criteria Page 9 1200.15.9. Air and Vacuum Relief Valves Air and vacuum relief valves shall be designed to allow large quantities of air to escape out the orifice when the pipeline is being filled and shall close watertight when water enters the valve. The valve shall also allow large quantities of air to enter the pipeline when the pipeline is being drained, or when a break has occurred, to break the vacuum. The valve shall consist of a body, cover, baffle, float and seat. The float shall be stainless steel designed to withstand a maximum pressure of 1,000 psi. All material shall conform to ASTM A126 GR. B and ASTM A240. Air and vacuum valves shall be installed in a vault in accordance with Standard Drawing No. 200-1. 1200.15.10. Blow-off Assembly Blow offs shall not be allowed as a permanent part of the system. Dead end lines shall have a hydrant installed. 1200.15.11. Vaults Vaults may be precast or poured in place and shall be constructed in accordance with these Standards and Specifications. Precast vaults shall be so designed that all joints and corners are waterproof. Precast and poured-in-place vaults shall be made waterproof after construction by use of sealants, epoxies or other approved methods. The vault roof shall be designed to support the overhead fill, any surcharge and an H-20 traffic loading. Particular care shall be taken in selecting precast vaults that the application not be one of either shallow or deep cover over the roof. Should the cover over the roof be less than 2½ feet or more than 5 feet, concern for adequacy of the roof, or the ability to remove and replace a one-piece roof slab resting upon deflecting side walls, may dictate a poured-in-place vault. 1200.15.12. Manholes Refer to Section 1300.10.4, Manholes, of these Standards and Specifications. 1200.15.13. Manhole Base Slabs and Base Beams Refer to Section 1300.10.5, Manhole Base Slabs and Base Beams, of these Standards and Specifications. 1200.15.14. Sump Pits for Vaults and Manholes Sumps are required for vaults or manholes in areas where there is a history of seepage into existing vaults and in all pressure regulating valve installations, as determined by the City Engineer. A gravity drain line or sump pump shall be used in conjunction with a sump where telemetry equipment is to be installed. All electrical work shall be designed for a wet environment. Telemetry equipment shall be above ground in a suitable enclosure. ---PAGE BREAK--- Standards and Specifications Section 1200 Water Supply Facilities Design Criteria Page 10 1200.15.15. Vent Pipes Unless otherwise approved by the City Engineer, vent pipes shall be used in vaults and pits to allow gases to escape. Installations that contain electrical equipment shall have a blower attached to the vent system. Vent pipes shall be field located at the nearest intersection of the street property line and the side lot line. Refer to Standard Drawings No.200 -7 for industrial and 200-15 for residential areas. Above ground vent pipe shall be 6 inch nominal diameter galvanized steel pipe, Schedule 40, conforming to ASTM. Standard Designation A 53. The vent screen shall be a ¾ inch No. 9-11 flattened expanded galvanized metal screen. Below ground vent pipe shall be 6-inch, scheduled 40 PVC with glued joints. A PVC glued joint by standard pipe thread female adapter shall be used to connect the steel pipe to the PVC pipe at ground level. 1200.15.16. Corrosion Protection Systems All ductile iron pipe shall be wrapped (AWWA Specifications and Drawing 200-8), boned, and a cathodic protection system provided. Such system shall be designed by people experienced in that area of work. 1200.15.17. Tracer Wire A No. 12 AWG stranded copper wire shall be attached to all pipe, for the purpose of future location, as detailed on Standard Drawing No. 200-4. Locate tape shall be placed above the bedding material or 18 inches above the pipe. 1200.15.18. Bedding Materials Bedding materials shall be in accordance with Section 1004.14, Bedding for Pipelines and Service Lines, of these Standards and Specifications. 1200.15.19. Concrete All concrete will conform to City standards for Portland Cement Concrete Work as specified in Section 600, Concrete Work, of these Standards and Specifications. 1200.15.20. Plastic Liner Pipe (Sliplining) Water main sliplining materials may only be used at the sole discretion of the City Engineer. 1200.15.21. Steel Casings for Bores Steel casing pipe shall comply with all applicable requirements of Section 1300.10.9, Steel Casings for Bores, of these Standards and Specifications. 1200.16. Taps Water taps are generally ¾ inch for residential use and designed to meet the demand for commercial use. It is recommended that commercial taps be oversized and an appropriate meter be installed for the proposed building use. ---PAGE BREAK--- Standards and Specifications Section 1200 Water Supply Facilities Design Criteria Page 11 1200.16.1. Service and Fire Lines Service lines shall be of a size adequate to supply the requirements of the property being served. The minimum size line shall be ¾ inch. The only acceptable materials for a service line are seamless copper tube, PVC, or wrapped ductile iron pipe. Plastic pipe will not be accepted as service pipe material for services less than 3 inches in diameter. All service pipes shall conform to one of the following specifications: a. Seamless copper tube of the type designated as “Type K” (soft) in the industry shall be used for service lines ¾ inch through 2 inches. b. PVC pressure pipe conforming to the AWWA C900 will be used for all service lines 3 inches or larger. Service lines shall be of the same type material from beginning to end, unless the appropriate insulator is installed at the junctions of dissimilar metals as approved by the City Engineer. Residential service lines and meter pits shall be paired at the property line wherever possible. 1200.17. Meters All meter yokes shall be installed shall be in accordance with these Standards and Specifications. 1200.17.1. Size of Meter The City Engineer may allow the installation of a meter a size smaller than the service pipe in cases where the full capacity of a service pipe is not required. Selection of the appropriate service line and meter will be determined by the applicant’s engineer and approved by the City Engineer on the basis of: a. Number of fixtures b. Length of service line c. Total gpm required d. Possible future expansion of use 1200.17.2. Small Water Meters Meters compatible with the utility system are paid for with the tap application. Meter sizes ⅝ inch through 2 inch are to be installed by the Public Works Department in outside pits or vaults. 1200.17.3. Large Meters (3 in and larger) Meters in sizes 3 inches through 6 inches, regardless of type of installation, shall be compound type meters. Large meters will be set by the pipeline contractor under City inspection. ---PAGE BREAK--- Standards and Specifications Section 1200 Water Supply Facilities Design Criteria Page 12 Specifications will be furnished upon request for meters larger than 6 inches or for installations where the service requirements are such that a meter other than the type mentioned above shall be required. 1200.17.4. Outside Meter Settings All outside meters shall be installed in a horizontal position and housed in a meter pit or vault, and shall conform to Standard Drawings No. 200-10a and No. 200-10b. 1200.17.5. Inside Meter Setting and Remote Readers Inside meters will only be used with special approval of the City Engineer. All inside meter settings shall be installed in a manner which will allow free access and adequate room for inspection and maintenance and will protect the meter from freezing. Meters installed inside buildings shall be not more than 18 inches from the wall through which the service pipe enters the building unless otherwise approved in writing by the City Engineer. The installation of the remote water meter shall conform to the following: a. The meter setting shall be installed in the basement, a utility closet, or similar area which will allow free and easy access and adequate room for installation, inspection, and maintenance. b. The meter yoke shall be a minimum of 12 inches and a maximum of 4 feet above floor level in a horizontal position and have a minimum of 1 foot clearance from all surrounding obstructions. c. A ball or gate valve shall be installed on both the upstream and sides of the water meter. d. All fittings shall be brass or copper. e. Remote touch pad shall be accessible outside the building. Inside meter settings will not be allowed in crawl spaces, closets or other places where free and easy access is not provided. Meter sizes 1½ inch and 2 inch installed inside buildings shall be provided with a floor drain. 1200.17.6. Meter Bypass Line A bypass line shall be required for all domestic service meters 1½ inch and larger, whether installed in an outside or inside a building, unless otherwise approved by the City Engineer. Bypass lines shall contain a lockable independent control valve and shall contain no tees, plugs, or other outlets through which water could be withdrawn, as indicated on Standard Drawings No. 200-10b. Bypass lines are not allowed on irrigation meters. ---PAGE BREAK--- Standards and Specifications Section 1200 Water Supply Facilities Design Criteria Page 13 1200.17.7. Backflow Prevention Devices Customer water connections to hazardous systems must have appropriate backflow prevention devices as shown in Table 1200-2 below. Residential services which have an alternate water supply, such as a well, need a reduced pressure backflow preventer. Table 1200-2. Backflow Prevention Devices, Assemblies and Methods1 Degree of Hazard Device, Assembly or Method Pollution (Low Hazard) Contamination (High Hazard) Installation Air Gap Back Siphonage Back Siphonage See Table 1200-3 Atmospheric Vacuum Breaker (not to be subjected to continuous pressure for more than 12 hours in any 24 hour period. Back Siphonage Back Siphonage Upright position. No valves Minimum of 6 in. (152 mm) or listed distance above all piping and flood level rim of receptor. Spill-Proof Pressure- Type Vacuum Breaker Back Siphonage Back Siphonage Upright position. Minimum of 6 in. (152 mm) or listed distance above all piping and flood level rim of receptor. Double Check Valve Backflow Preventer Back Siphonage and Back Pressure Horizontal, unless otherwise listed. Requires 1 ft. (305 mm) minimum clearance at bottom for maintenance. May need platform/ladder for test and repair. Does not discharge water. Pressure Vacuum Breaker Back Siphonage Back Siphonage Upright position. May have valves Minimum of 1 ft. (305 mm) above all piping and flood level rim of receptor. May discharge water. Reduced Pressure Principle Backflow Preventer Back Siphonage and Back Pressure Back Siphonage and Back Pressure Horizontal unless otherwise listed. Requires 1 ft. (305 mm) minimum clearance at bottom for maintenance. May need platform/ladder for test and repair. May discharge water. 1 Source: Colorado Cross-Connection Control Manual – March 2000, Chapter 4 ---PAGE BREAK--- Standards and Specifications Section 1200 Water Supply Facilities Design Criteria Page 14 Table 1200-3. Minimum Air Gaps for Water Distribution****2 Fixtures When not affected by side walls* inches (mm) When affected by side walls** inches (mm) Effective openings*** not greater than ½ in. (12.7 mm) in diameter 1 (25.4) 1-1/12 (38) Effective openings*** not greater than ¾ in. (19.1 mm) in diameter 1-1/2 (38) 2-1/4 (57) Effective openings*** not greater than 1 in. (25.4 mm) in diameter 2 (51) 3 (76) Effective openings*** greater than 1 in. (25.4 mm) in diameter 2 times diameter of effective opening 3 times diameter of effective opening * Side walls, ribs or similar obstructions do not affect air gaps when spaced from the inside edge of the spout opening a distance greater than three times the diameter of the effective opening for a single wall, or a distance greater than four times the effective opening for two intersecting walls. Vertical walls, ribs or similar obstructions extending from the water surface to or above the horizontal plane of the spout opening other than specified in * above. The effect of three or more such vertical walls or ribs has not been determined. In such cases, the air gap shall be measured from the top of the wall. The effective opening shall be the minimum cross-sectional area at the seat of the control valve or the supply pipe or tubing which feeds the device or outlet. If two or more lines supply one outlet, the effective opening shall be the sum of the cross-sectional areas of the individual supply lines or the area of the single outlet, whichever is smaller. Air gaps less than 1 inch (25.4 mm) shall only be approved as a permanent part of a listed assembly that has been tested under actual backflow conditions with vacuums of 0 to 25 inches (635 mm) of mercury. 1200.17.8. Valves for Use with Meters Gate valves smaller than 3-inch to be used with copper service pipe shall be brass, with non-rising stems and solid wedge disc. Gate valves shall meet the requirements of AWWA Standard C800. Valves 3 inches and larger for use with service pipse shall be gate valves with cast iron bodies conforming to the AWWA C500. All gate valves larger than 3 inches shall be supported by adjustable steel valve supports. Also refer to Standard Drawing No. 200- 10b of these Standards and Specifications. 1200.17.9. Meter Yokes (Line Setters) A yoke is a metal pipe frame attached to the inlet and outlet sides of the meter providing support, and conveying water to the meter. Meter yokes shall be the appropriate laying length for the meter size. See Standard Drawing No. 200-10a. 2 Source: Colorado Cross-Connection Control Manual – March 2000, Chapter 4 ---PAGE BREAK--- Standards and Specifications Section 1200 Water Supply Facilities Design Criteria Page 15 To assure safety, the water meter setting shall provide a continuous, electrically conductive path around the water meter. If a bonding jumper is required, it shall be made of copper with fittings suitable for the bonding jumper and the water pipe material. The meter setting installation shall be in compliance with the NEC, Articles 100, 250-81, 250- 94, 250-112 and 250-115(a). 1200.17.10. Valve and Meter Supports Meter supports shall be a solid concrete block as shown in Standard Drawing No. 200- 10b. Fabricated metal supports shall be used to support valves 4 inches and larger. 1200.17.11. Residential Meter Pits and Covers Meter pits shall be 2 foot plastic or fiberglass pit in accordance with ASTM/D1505 and ASTM/D746. Meter pit covers shall be tight fitting with a double cover. The meter pit cover shall have a cast iron, cap type, top lid. A frost lid will be provided. The body of the meter pit ring shall be cast iron. See Standard Drawing No. 200-10a. 1200.17.12. Corporation Stops See Standard Drawing No. 200-10a. Corporation stops shall be ball valve type. 1200.17.13. Curb Stops Curb stops are set on the service line on the inlet side of the meter pit and provide a means to shut off the service line. Curb stops shall be buried a minimum of 4 feet 6 inches and a maximum of 5 feet. Placement of the curb stop and stop box shall be in accordance with Standard Drawing No. 200-10a. 1200.17.14. Curb Stop Service Boxes See Standard Drawing No. 200-10a. 1200.18. Modifications to Existing System Where an existing line is being abandoned or replaced, the connection to the line remaining in service shall be plugged or a short feet long) stub shall be capped. If there is a valve at the old connection, it may be closed and a cap or plug installed on the abandoned side. The valve box shall be removed. ---PAGE BREAK--- Standards and Specifications Section 1300 Design Criteria – Sanitary Sewer Facilities Page 1 Section 1300 Design Criteria – Wastewater Facilities 1300. DESIGN CRITERIA – WASTEWATER FACILITIES 2 1300.1. . 2 1300.2. DESIGN 2 1300.3. HYDRAULIC 2 1300.4. MINIMUM 3 1300.5. 3 1300.6. SERVICE 4 1300.7. LOCATION 4 1300.8. RELATION TO WATER 4 1300.9. UNDERDRAIN 5 1300.10. MATERIALS 5 1300.10.1. Wastewater Pipe 5 1300.10.2. Underdrain Pipe 5 1300.10.3. Plugs 5 1300.10.4. 5 1300.10.5. Manhole Base Slabs and Base 6 1300.10.6. 6 1300.10.7. Cast Iron 6 1300.10.8. Bedding 7 1300.10.9. Steel Casings for Bores – Highway or Railroad 7 1300.11. WASTEWATER LIFT STATIONS 8 1300.12. DESIGN 8 1300.12.1. Wet Well Construction 8 1300.12.2. Pumps and Pump Station 8 1300.12.3. Controls and . 9 1300.12.4. Site 9 ---PAGE BREAK--- Standards and Specifications Section 1300 Design Criteria – Sanitary Sewer Facilities Page 2 1300. Design Criteria – Wastewater Facilities 1300.1. General All extensions of and/or additions to the City wastewater systems will comply with the requirements of these Design Criteria for wastewater main and service line construction. 1300.2. Design Flow The design will include consideration of providing service for the entire area tributary to the outfall point. The following wastewater flow rates, which include infiltration, shall be used: User Type Unit Wastewater Flow Rate Residential 300 gallons/house/day Industrial 1,500 gallons/acre/day Commercial 1,000 gallons/acre/day Park/Recreation 50 gallons/acre/day Elementary Schools 20 gallons/student/day Jr. & Sr. High Schools 25 gallons/student/day Minimum residential population density, household density and land usage shall be as noted on an approved PUD and/or Plat, or as determined by the City Planning Dept. Wastewater flow peaking factors shall be computed using the following equation: PF = 21.2(population-0.2556 1 single-family house = 3.7 people, 1 multi-family unit = 2.5 people ) The peaking factor will not be less than 2 or greater than 5. 1300.3. Hydraulic Design Wastewater lines shall carry the peak design flow at build out at a maximum flow depth of 70% of the pipe diameter. The minimum velocity at the peak design flow rate shall be 2 feet per second. Where actual flow will be considerably below the design flow for several years, the City Engineer may require that the minimum velocity be attained by suitable grades at the partial peak design flow rate. Maximum allowable velocity shall not exceed 10 feet per second at 70% flow depth in the pipe. Care will be taken to design invert elevations at manholes in such a manner that the energy gradient is consistently falling in the direction of flow. In addition, when the velocity of an ---PAGE BREAK--- Standards and Specifications Section 1300 Design Criteria – Sanitary Sewer Facilities Page 3 upstream wastewater line entering a manhole at peak flow is above critical velocity, the hydraulic gradient shall be computed to insure that a surcharge will not occur at a service connection, and that the energy gradient will remain level across the manhole. Manholes at bends shall have a 0.2 foot drop. Straight manholes with the pipe run through do not need an additional drop. 1300.4. Minimum Grade Wastewater mains will be 8 inch diameter or larger. Service connections will be 4 inch diameter or larger. Six inch diameter wastewater mains may be installed under special conditions where no more than 4 residential connections are to be made if the design is approved by the City Engineer or on dead ends. The following minimum grades will apply: Wastewater Line Diameter (Inch) Minimum Grade (Percent) 4 2.0 or 1/4 inch/foot 6 1.0 or 1/8 inch/foot 8 0.40 10 0.28 12 0.22 15 0.15 18 0.12 21 or larger As approved by the City Engineer Larger wastewater lines WILL NOT be installed with the sole intent of reducing grade requirements. Wastewater mains will ordinarily have a minimum of 8 feet of cover to finished ground surface. Where this will provide less than 9 feet of elevation difference between the finished lot grade at building line and the top of the wastewater main, it will be indicated on the plans that the lot is served by a shallow wastewater line and appropriate elevation information will be given. Where pipe has less than 4 feet of cover, provisions will be made to protect the pipe from impact, loading and freezing. Wastewater mains will be extended at least 10 feet uphill from the lowest lot corner of the uppermost lot to be served adjacent to the wastewater main. Wastewater service may terminate in a manhole if the inverts match the invert of the main wastewater service line. Wastewater mains will be stubbed out from manholes with suitable size pipe wherever future extension of the wastewater line is anticipated. 1300.5. Manholes Manholes will be provided at every change in direction, grade, or at connection with another wastewater main; maximum spacing will be 400 feet for all lines. Wastewater lines will be straight and not curved between manholes, both in line and grade. ---PAGE BREAK--- Standards and Specifications Section 1300 Design Criteria – Sanitary Sewer Facilities Page 4 Manholes will be 48 inches diameter for lines 8 inches to 15 inches diameter, 60 inches for lines 18 inches to 21 inches diameter, and 72 inches for lines 24 inches to 30 inches diameter. Specially designed vaults are required for pipes greater than 30 inches in diameter. Outside drop manholes will be provided for a wastewater line entering a manhole at an elevation 24 inches or more above the manhole invert. Where the difference in elevation is less than 24 inches, the invert will be filleted to prevent solids deposition. 1300.6. Service Connections Wyes will be provided in the wastewater main for service connections at each lot or building site. Unless specific approval is obtained in writing from the City Engineer, all sanitary wastewater service lines shall have a minimum depth of 3 feet. Fittings will be angled upwards so that the upper invert of one-eighth bend connected to the fitting will have an elevation equal to or higher than the inside crown of the wastewater main. Riser connections will be installed where the elevation of the top of the fitting is more than 12 feet below finished ground. Riser connections will ordinarily reach to a grade 10 feet below finished ground surfaces. 1300.7. Location Details Unless approved otherwise by the City Engineer, wastewater mains installed in local or collector streets will be located 10 feet east or south of the centerline of these streets. Service connections will not be permitted to cross an arterial street without written permission from the City Engineer. The main will be installed to provide proper maintenance access to manholes. 1300.8. Relation to Water Mains Local wastewater lines will be located a minimum of 10 feet, horizontally, from existing or proposed water mains (centerline distance). Trunk lines (greater than 12 inches diameter) shall have 10 feet clearance between the pipes. Wastewater pipe may be encased in reinforced concrete. Where wastewater lines cross water mains, the wastewater pipe will be a minimum of 18 inches below the water main. If this clear distance is not feasible, the crossing must be designed and constructed so as to protect the water main. The crossing design must be approved by the City Engineer. Wastewater line protection may be by concrete encasement. The encasement will be at least 6 inches thick around the entire pipe and will extend a distance of 10 feet on either side of the water main crossing. An alternate protection may be the installation of C900 pipe for the wastewater line. In all cases, suitable backfill or other structural protection will be provided to preclude settling and/or failure of the higher pipe. ---PAGE BREAK--- Standards and Specifications Section 1300 Design Criteria – Sanitary Sewer Facilities Page 5 1300.9. Underdrain Pipe Underdrain pipe will be installed wherever possible. Underdrain pipe will be installed unless the City Engineer approves otherwise. Any such system shall NOT be tied into the sanitary wastewater collection system in any manner. 1300.10. Materials 1300.10.1. Wastewater Pipe Unless otherwise approved by the City Engineer, all wastewater pipe and fittings will be Polyvinyl Chloride (PVC) and will conform to the requirements of ASTM D3034, SDR 35. Pipe buried greater than 18 feet shall be C900. Transitions shall be at manholes. All PVC pipe and fittings will be subject to inspection by the City in order to reject materials that fail to conform to the requirements of these Standards and Specifications. Defects will be marked so as not to disfigure the rejected pipe. Rejected pipe will be removed from the job site within 24 hours. All joints will be factory prepared compression type (Elastomeric Gasket Joint), providing a water-tight seal. Solvent cement joints will not be used. 1300.10.2. Underdrain Pipe If required as described in Section 1300.9 of these Standards and Specifications, underdrain pipe will be provided with joints which will prevent any shifting or misalignment of the line. No finger jointing allowed. Where underdrains are to be constructed under wastewater mains, clean outs will be provided at each manhole for the underdrain with wyes. Tees shall not be permitted. Suitable fittings will be provided which will allow construction of clean-outs and bends at manholes. Unless otherwise approved by the City Engineer, all underdrain pipe and fittings will be Polyvinyl Chloride (PVC) and will conform to the requirements of ASTM D3034, SDR 35. Pipe shall be perforated in the lower quadrant. Underdrains will be encased in a filter fabric sock. 1300.10.3. Plugs A compression stop as recommended by the pipe manufacturer will be provided to seal the end joint of wye connections and dead-end stubs. At dead-end stubs, away from a manhole or where wyes are installed, locations shall be marked with a green 2x4 post with a minimum 24 inches exposed above ground and a buried piece of rebar. 1300.10.4. Manholes Manholes may be constructed of cast-in-place concrete or precast concrete. Concrete precast reinforced risers and tops will conform to ASTM Designation C-478 except that wall thickness may be either wall A or wall B as described in ASTM Designation C-76. Manholes will conform to details shown on Standard Drawings No. 300-1 through No. 300- 3 unless otherwise approved by the City Engineer. Cones will be of the eccentric type. ---PAGE BREAK--- Standards and Specifications Section 1300 Design Criteria – Sanitary Sewer Facilities Page 6 The top of the manhole vault shall be a minimum of 12 inches and a maximum of 18 inches below the finished street or ground surface elevation. Concrete extension risers or collars shall be used to bring the manhole ring and cover up to finished street or ground surface elevation. Manhole rings and covers shall be designed for H-20 traffic loading. Steps must carry a load of 1,000 pounds when projected 6 inches from the wall and 1,500 pounds when projected 4 inches from the wall without permanent deformation. Steps will be one-half inch diameter steel reinforcing rod completely encapsulated in Copolymer Polypropylene. Steps will be spaced as shown on Standard Drawing No. 300-1. The maximum distance from the finished ground (street) surface to the first step will be 18 inches. Mortar for manholes will be mixed in the following proportions by volume: One part Portland cement; one-half part hydrated lime; and three parts sand. Pre-mixed masonry mortar may be also used. The cement, lime, and sand will be thoroughly mixed dry and only enough water added to form a mortar of proper consistency. Mortar will be used within one hour after mixing with no retempering permitted. Mortar that has taken a partial set will not be used. 1300.10.5. Manhole Base Slabs and Base Beams Manhole base slabs may be poured in place. Precast will be considered by the City Engineer in the event of traffic or safety considerations. Where possible, inverts will be the PVC pipe with the top half cut out. The slab shall be designed to uniformly support the earth load and any other reasonable loads that may occur. The minimum slab thickness shall be 6 inches. Concrete minimum strength is 3,000 psi. The minimum reinforcement shall be #4 rebar at 8 inches OC each way for depths up to 15 feet. For manholes 15 feet deep or greater, the slab shall be structurally designed by a professional engineer. 1300.10.6. Concrete Concrete will conform to Section 600, Concrete Work, of these Standards and Specifications. Type II cement will be used. 1300.10.7. Cast Iron Fittings All cast iron manhole rings and covers, and other iron castings will be made of tough gray pig iron conforming to ASTM Designation A-48 and will be free from cracks, holes, swells, and cold shuts, and will have a smooth workman-like finish. Castings will conform to details shown on Standard Drawings No. 300-1 through No. 300-3 unless otherwise approved by the City Engineer. Cast iron manhole rings and covers will be of the NEENAH model R-1683 (or approved equal) and will have a combined weight of not less that 400 pounds. All metal bearing surfaces between the ring and cover will be machined or fabricated to insure good seating. Manhole lids will be provided with non-slip pattern in surface which lies flush with the elevation of the ring. Lids shall be furnished with the word "WASTEWATER" cast on top. ---PAGE BREAK--- Standards and Specifications Section 1300 Design Criteria – Sanitary Sewer Facilities Page 7 1300.10.8. Bedding Materials Bedding materials shall be in conformance with Section 1004.1, Bedding for Pipelines and Service Lines, of these Standards and Specifications. Underdrains will be encased in ¾” washed rock. 1300.10.9. Steel Casings for Bores – Highway or Railroad Casing pipe and joints shall be uniformly thick steel construction approved by the railroad or CDOT and shall be capable in its entirety of withstanding load of railroad roadbed, track, or traffic, and shall also be constructed so as to prevent leakage of any matter from the casing or conduit throughout its length under track and railroad right-of- way. The casing shall be installed with even bearing throughout its length and, to prevent formation of standing liquids, shall slope to one end. Wall thickness of the casing must be no less than that specified in the attached steel casing pipe wall thickness chart. Inside diameter of the casing shall be at least 10% larger than the outside diameter of the carrier pipe but no less than 2 inches greater than largest outside diameter of carrier pipe, joints or couplings. Minimum Thickness Diameter of Casing Pipe Casing Diameter Minimum Thickness 12" or less ¼” (0.2500”) 14"-18" 5/16" (0.3125") 20"-22" 3/8" (0.3750") 24"-28" 7/16" (0.4375”) 30"-34" 1/2" (0.5000") 36"-42" 9/16" (0.5625”) 44"-48" 5/8" (0.6250") This chart is only for smooth steel casing pipes with minimum yield strength of 35,000 psi. Pipe casing design may need agency approval and/or a license agreement. Voids between the pipe and casing shall be filled with sand or the pipe supported with spacers sufficient to prevent movement. ---PAGE BREAK--- Standards and Specifications Section 1300 Design Criteria – Sanitary Sewer Facilities Page 8 1300.11. Wastewater Lift Stations Lift stations will be allowed only in accordance with City PUD Standards, Resolution 2003- 30, Section 5. In those locations that cannot be served by gravity into the existing City system, the City may approve the construction of a sewage lift station. The Developer must provide the City Engineer with a complete set of design calculations and drawings for review and acceptance by the City Engineer in compliance with Section 105, Plans and Specifications, of these Standards and Specifications. The wastewater lift station must satisfy all of the requirements of the Colorado Department of Public Health and the Environment (CDPHE) and of these Standards and Specifications. The City will require that the Developer's engineer prepare the "Application for Site Approval" for the submittal to the Colorado Department of Health and a set of as- built drawings of the sewage lift station in accordance with Section 106, Acceptance Procedures, of these Standards and Specifications Upon completion of the lift station, the Contractor shall also provide the City with two copies of an "Operation and Maintenance Manual" for the lift station. 1300.12. Design Criteria 1300.12.1. Wet Well Construction The wet well will consist of a cast-in-place reinforced concrete structure divided into two compartments. The two compartments will be interconnected with a valve or gate. The dual compartments will allow the draining of one compartment for cleaning or maintenance without affecting the operation of the station. A division box will be provided upstream of the wet well to allow the sewage lift station flows to be directed into either or both of the wet well compartments. A removable basket screen will be provided in the inflow into each wet well compartment to collect debris. 1300.12.2. Pumps and Pump Station Pumps will be either vertical, close-coupled, vacuum primed, non clog pumps installed directly above the wet well, or centrifugal pumps of an acceptable design installed in a dry well adjacent to the wet well. Submersible pumps will not be allowed unless site conditions specifically warrant, and use of submersible pumps will require the written approval of the City Engineer. The station will be designed utilizing a minimum of three pumps and shall be capable of pumping the peak design flow with one pump out of service. All pump equipment will be manufactured and supplied by the same company. The station will be an above-ground structure sized to accommodate all of the pumps, electrical equipment and controls required to operate the facility. The station shall have redundant controls and a telephone alarm system to notify maintenance staff in the event of an emergency. Generator controls shall also be connected to the emergency dialer system. The station shall conform to all current adopted City of Lafayette codes and industry standards relative to safety. ---PAGE BREAK--- Standards and Specifications Section 1300 Design Criteria – Sanitary Sewer Facilities Page 9 The station will be lighted, heated and well ventilated, and will be designed for easy expansion if required by the City Engineer. The architectural finish of the station will blend with that of the surrounding architecture as much as possible. A standby generator, capable of operating the entire station for a minimum of four hours, shall be located outside the building in an all-weather sound-reducing enclosure. 1300.12.3. Controls and Telemetry Pump operation will feature automatic sequencing of the pump operation to balance pump wear. Pumps will be actuated at predetermined wet well levels controlled by redundant control systems. A radio or phone telemetry system will be incorporated into the system to automatically contact the City in case of an emergency. The telemetry system will be equipped with several channels so it will be capable of differentiating between a variety of emergency conditions including high and low wet well levels, pump failures and power failure. The telemetry system shall be compatible with the City's system and will be reviewed and accepted by the City Engineer and the Information Systems Department prior to installation. The controls, telemetry equipment, miscellaneous electrical equipment and automatic power switch will be installed in a control room located on the above ground floor of the pump station. 1300.12.4. Site Improvements A 6 foot high vinyl coated chain link fence with barbed wire will be installed around the perimeter of the wastewater lift station site. Upon completion of the lift station construction all disturbed areas within the site will be fertilized, seeded and mulched in accordance with Section 830.00, Seeding Specifications, of these Standards and Specifications. Depending on site location, additional landscaping improvements may be required by the City Engineer. ---PAGE BREAK--- Standards and Specifications Section 1400 Design Criteria – City Streets PAGE 1 Section 1400 Design Criteria City Streets 1400. DESIGN CRITERIA – CITY 2 1400.1. GEOMETRIC CROSS-SECTIONS AND STREET 2 1400.1.1. 2 1400.1.2. Emergency 2 1400.1.3. 2 1400.1.4. Street Classification and 2 1400.2. HALF STREETS 4 1400.3. STRUCTURAL SECTIONS 4 1400.3.1. Structural Sections for 4 1400.3.2. Structural Sections for Parking 5 1400.4. HORIZONTAL 5 1400.5. VERTICAL ALIGNMENT 5 1400.6. CUL-DE-SACS 5 1400.7. MAJOR 5 1400.8. DESIGN ELEMENT 6 1400.9. REQUIREMENTS OF OTHER 6 Drawings 1400-1 Typical Section 120th 1400-2 Typical Section South Boulder Rd. Street 1400-3 Typical Section Baseline Rd. 1400-4 Minimum Collector Street 1400-5 Local Street 1400-6 Small Local Street, 25 Houses 1400-6a Local Street – Parking on One Side 1400-6b Local Street – No Parking 1400-7 Rural Road Section 1400-8 Sight Distance 1400-9 Cul-de-Sacs 1400-10 Drive Cut Location & Spacing 1400-11 Monolithic Integral Curbwalk 1400-12 Vertical Curb Section 1400-13 Cross Pan & Curb Return Fillets 1400-14 Drive Cut 1400-15 Curb Ramp Detail 1400-16 Final Overlay 1400-17 Fire Truck Turning Radius ---PAGE BREAK--- Standards and Specifications Section 1400 Design Criteria – City Streets PAGE 2 Section 1400 Design Criteria City Streets 1400. Design Criteria – City Streets Street design, construction and right-of-way (ROW) requirements will conform to the provisions of these Standards and Specifications. Pavement design criteria for various street types are listed on Table 1400-3. The requirements of the City’s subdivision and zoning ordinances and the City’s Comprehensive Master Plan will be met. Throughout this section, reference to a “qualified soils engineer” shall mean a soils engineer who is a Registered Professional Engineer licensed to practice in Colorado. 1400.1. Geometric Cross-Sections and Street Layout Developments shall include arterial and collector streets as shown in the City of Lafayette Comprehensive Plan. Street cross-sections shall conform to those of the street designation. Street cross-sections are shown in Standard Drawings 1400-1 through 1400- 7 as selected by the City Engineer. Generally, local residential cross-sections will be used in areas where average daily traffic (ADT) is not likely to exceed 1,500 vehicles per day. Collector and arterial streets will be constructed whenever the alignment of the proposed street is generally the same as the collector and arterial streets shown on the Comprehensive Plan and whenever a traffic engineering analysis of the future traffic volumes indicates the need of a cross-section greater than that of a local service street. Additional right of way may be required to satisfy other criteria contained in these Standards and Specifications. Areas outside the ROW will be contour graded, compacted and sloped, as required for proper drainage, soil stability and maintenance accessibility. 1400.1.1. Alleys All alleys, when permitted by the City Engineer, shall be paved to a full width and shall provide paved access to a paved street at both ends. Minimum right-of-way and roadway widths are given in Table 1400-2. Maintenance of alleys is the responsibility of the developer or local HOA in perpetuity. Inverted crowns are not allowed in alleys if they are paved with asphalt. 1400.1.2. Emergency Access Emergency access roads shall have a minimum right-of-way width of 20 feet and a minimum roadway width of 16 feet. Building fire access shall allow full movement of a fire truck. Drawing 1400-17 or AASHTO BUS45 may be used as a turning template. 1400.1.3. Intersections Intersections shall be designed to provide for the safety of motorists, pedestrians and bicyclists. 1400.1.4. Street Classification and Sizing Initial street sizing shall be according to Table 1400-1. ---PAGE BREAK--- Standards and Specifications Section 1400 Design Criteria – City Streets PAGE 3 TABLE 1400-1. STREET SIZING Street Type ADT Range Arterial (2 lane) 3,000 to 15,000 Collector 1,000 to 3,000 Local 100 to 1,500 Minor Local (<25 houses) 0 to 300 These ranges shall not be used in the future to curtail access, close streets or cause other actions which will shift unanticipated traffic to other streets. TABLE 1400-2. STREET DESIGN CRITERIA Design Element Baseline Road S Boulder Rd/120th Collector Arterial Local Code Local Min. Small Local Alleys Drawing # 1400-3 1400-1,2 1400-4 1400-5 1400-6 R.O.W. 120′ 70/80′ 50′ 50′ 45′ 41′ 20′ Flow Line Width 33’ 54’ 39’ 38′ 36’ 32’ 18’ Total Through Lanes 4 4 2 2 2 2 Travel Lanes 12’ 12’ 12.5’ 12′ 11’ 10’ Bike Lane Width 3’ 3’ Planted Raised Median 20’ 16’ Curb & Gutter 6” Barrier with 2’ Gutter Parking Lane N/P N/P 7’ 7’ 7’ 7’ N/P Plant Strip 8’ 8’ Sidewalk Width 8’ D 8’ D 5’ 5’ 4’ 4’ Utility Easement (outside ROW) 0 10′/12′ 8’ 8’ 8’ 8’ Flow Line Curb Radius 50’ min 50’ min 40’ min 25’ min 25’ min 25’ 15’ max Typical Posted Speed Limit 35 mph 35 mph 25 mph 25 mph 25 mph 25 mph Min. Cross Slope 2% 2% 2% 2% 2% 2% 2% Min. Center Line Radius 675’ 675’ 260’ 260’ 100’ 100’ 60’ Max. Street Grade 5% 5% 7% 7% 7% 7% 7% Min. Flow Line Grade 0.75% 0.75% 0.75% 0.75% 0.75% 0.75% 0.75% Max. Grade at Intersection 2% for 300’ 2% for 300’ 4% for 150’ 4% for 150’ 4% for 150’ 4% for 150’ 4% for 150’ D = Detached N/P = Not Permitted Alternate sections with no parking may be allowed if Note – See special sections for Baseline Road, S. Boulder Road, 120 two off-street parking spaces (excluding driveways) are provided within 300 feet for each dwelling unit. th – Mountable curb (drawing 1400-11) in residential areas where driveway locations are not known. Street. ---PAGE BREAK--- Standards and Specifications Section 1400 Design Criteria – City Streets PAGE 4 1400.2. Half Streets Half streets are not allowed. 1400.3. Structural Sections 1400.3.1. Structural Sections for Streets Structural sections for streets will be designed by a qualified soils engineer based on the appropriate Equivalent (18 Kip) Daily Load Applications (EDLA) for a 20 year service life and the subgrade support analysis. The soils analysis shall be performed in accordance with AASHTO standard methods of surveying and sampling soils. The field investigation shall consist of boring subgrade soils to a depth of at least 4 feet below proposed subgrade elevation (9 feet below proposed subgrade on arterial roadways), at spacings of not more than 250 feet, or a minimum of one boring for each section of street. The Hveem Stabilometer design method will be used for arterial streets, and either the Hveem Stabilometer or the California Bearing Ratio (CBR) design method will be used for all other streets. The structural section will consist of a granular base with an asphaltic concrete wearing surface or granular base and concrete pavements. The preliminary structural section will be a 20-year design section with a temporary cross slope of 1.2% - 1.6% from flow line to centerline as shown in drawing 1400-16. The following standards provide the minimum acceptable pavement sections for public roadways in Lafayette. These pavement thicknesses may be used for preliminary planning purposes. Final pavement designs must be based on actual subgrade support test results with EDLA values as shown in Table 1400-3. TABLE 1400-3. LOADING REQUIREMENTS / MINIMUM SECTION EDLA Composite Section Concrete Section Base Asphalt Base Concrete Local Residential <25 houses 20 8″ 3″ 6″ 6″ >25 houses 30 8″ 3″ 6″ 6″ Collector Residential Zoning 30 8″ 4″ 6″ 6″ Commercial/Industrial Zoning 100 8″ 4″ 6″ 6″ Arterial 200 9″ 5″ 9″ 10″ Where there are CH or CL soils, a soil swell test will be completed under a 250 lb./square foot load. In areas showing 2 to 4% swell upon wetting, the pavement design will include subgrade modification with fly ash, lime, or other treatment approved by the City Engineer. Soils with a swell potential greater than 4% will be removed and replaced with nonexpansive material. Replacement of existing material with moisture conditioning at 0 to of optimum will only be allowed if the subgrade will pass a proof roll test. All swelling soils mitigation plans must be approved by the City Engineer. The final layer of asphalt concrete will be installed in residential developments after 80% of the Certificates of Occupancy are received. The final layer of asphalt will be installed in commercial or industrial areas at the sole discretion of the City Engineer. Edges will be milled to provide 2% cross slope and a uniform thickness top lift of 1-1/2 inches. ---PAGE BREAK--- Standards and Specifications Section 1400 Design Criteria – City Streets PAGE 5 Portland Cement concrete pavement designs may be allowed with City Engineer approval of the design thickness. 1400.3.2. Structural Sections for Parking Lots Maintenance and repair of parking lots is the responsibility of the developer and/or the owner of the property per Municipal Code Sections 26-18-9 and 26-20-7. Design is not City reviewed. 1400.4. Horizontal Alignment Streets will generally be aligned to bear a reasonable relationship to topography. Horizontal curves will conform to the street design criteria listed in Table 1400-2. Minimum spacing between intersection centerlines is shown in Table 1400-4. TABLE 1400-4. MINIMUM SPACING BETWEEN INTERSECTION CENTERLINES Street Type Spacing Local Residential 300' Collector 500' Arterial 1300' Streets will intersect or connect to other streets as closely as possible to right angles but will not deviate more than 10 degrees from a right angle. Horizontal and vertical alignment and right of way limits will be coordinated so as not to obstruct sight distance at intersections, in accordance with Standard Drawing No. 1400-8. Curb return radii will be as shown on Table 1400-2. Where two different street types connect, the larger curb return radius will apply. Minimum radius of a street being intersected shall be 285 feet. 1400.5. Vertical Alignment Minimum street flowline profile grades will be as shown on Table 1400-2. Where a street is curved and minimum profile grade is desired, the centerline grade will be adjusted so that the flow line grade on the outside of the radius will be no less than the minimum street grade specified on Table 1400-2. Plans shall show flow line profiles. 1400.6. Cul-de-sacs Cul-de-sacs will conform to Standard Drawing No. 1400-9. Residential cul-de-sacs shall not exceed 500 feet in length without emergency access. Multi-family, commercial, or industrial cul-de-sacs shall not be longer than 350 feet without emergency access. 1400.7. Major Structures Major structures, such as retaining walls, box culverts and bridges, that are appurtenant to proposed street and/or parking lot construction, will conform to the structural design and ---PAGE BREAK--- Standards and Specifications Section 1400 Design Criteria – City Streets PAGE 6 loading requirements of the CDOT Standard Specifications for Road and Bridge Construction and the geometric and drainage requirements of the City Engineer. Plans and supporting calculations for major structures must be prepared by a qualified structural engineer who is a Registered Professional Engineer licensed to practice in Colorado. 1400.8. Design Element Coordination Horizontal and vertical alignment continuity will be provided between new and existing streets to achieve safe and aesthetically pleasing transitions. Sufficient data on existing facilities will be depicted on plans, and limits of construction will be designated so as to assure that the desired continuity will be achieved. Drainage and utility facilities are to comply with all applicable sections of these Standards and Specifications and are to be fully coordinated with the street design and proposed construction. These facilities will be staged to eliminate grade and alignment conflicts and unnecessary damage to existing or newly constructed facilities. 1400.9. Requirements of Other Jurisdictions Where proposed street construction will affect other agencies such as the CDOT, adjacent cities and counties or ditch companies, construction will be subject to the review of said agencies. Generally, where more than one requirement is imposed, the more restrictive requirement will govern. Exceptions must be authorized by the City Engineer in writing. ---PAGE BREAK--- STANDARDS AND SPECIFICATIONS SECTION 1500 STORM DRAINAGE DESIGN AND TECHNICAL CRITERIA PAGE 1 Section 1500 Design Criteria Storm Drainage Rev. 8-18-12 1500. DESIGN CRITERIA STORM DRAINAGE 2 1501. MINIMUM DESIGN CRITERIA 2 1501.1. GENERAL 2 1501.2. ANALYSIS AND ACCEPTABLE METHODS 2 1501.3. DESIGN METHODS 3 1501.4. COLORADO URBAN HYDROGRAPH PROCEDURE (CHUP) 3 1501.5. RATIONAL METHOD 5 1501.6. CRITERIA FOR STORM-FLOW ANALYSIS 5 1501.7. DETENTION POND DESIGN 6 1501.7.1. Detention Requirements 6 1501.7.2. Detention Computation Example 7 1501.7.3. Detention Pond Outlet Configuration (Figure 1500-3) 7 1501.7.4. Trickle Flow Control in Detention Areas 8 1501.7.5. Detention Pond Grading Requirements 8 1501.7.6. Detention Pond Embankment Protection 8 1502. DESIGN STANDARDS 8 1502.1. INITIAL AND MAJOR DESIGN STORM 8 1502.1.1. Initial Storm Provisions 1502.1.2. Major Storm Provisions 1502.2. DESIGN STORM FREQUENCIES 1502.3. RAINFALL INTENSITIES AND DESIGN STORMS 1502.4. RUNOFF COMPUTATION 1502.5. RUNOFF COEFFICIENTS 1502.6. TIME OF CONCENTRATION 1502.7. OPEN CHANNELS 1502.8. IRRIGATION DITCHES 1502.9. STORM DRAINAGE LINES AND STORM INLETS 1502.9.1. Storm Drainage Lines 1502.9.2. Storm Inlets 1502.10. CULVERTS 1502.11. STREET FLOW CAPACITIES 1503. DESIGN AIDS 1503.1. GENERAL 1503.2. ROUGHNESS COEFFCIENT 1503.3. DESIGN FORMS 1504. CHECKLIST FOR STORM DRAINAGE REPORTS AND CONSTRUCTION PLANS 1504.1. GENERAL 1504.2. PLAN SHEETS 1504.3. DRAINAGE PLANS 1504.4. CONSTRUCTION PLANS AND DETAILS 1504.5. PRELIMINARY DRAINAGE REPORT 1504.6. FINAL DRAINAGE REPORT 1504.7. CDPS STORMWATER COMPLIANCE 1504.7.1. Construction Site Runoff and Waste Control 1504.7.2. Storm System Pollution Control (Post Construction) ---PAGE BREAK--- STANDARDS AND SPECIFICATIONS SECTION 1500 STORM DRAINAGE DESIGN AND TECHNICAL CRITERIA PAGE 2 Section 1500 Design Criteria Storm Drainage 1500. Design Criteria Storm Drainage Note: This is a reconstruction of the previously adopted Storm Drainage Criteria in an electronic format. New NPDES Phase II requirements have been added as Section 1505. Section 1500 sets forth the minimum design and technical criteria and specifications for the analysis and design of drainage systems. All subdivision plats, planned unit developments, or any other proposed construction submitted for approval shall include adequate storm drainage system analysis and appropriate drainage system design before approval of any phase of construction will be made by the City Council or its designated representatives. Such analysis and design shall conform to the criteria set forth herein. Acknowledgements: The development of these storm drainage design and technical criteria was funded jointly by the City of Lafayette and Boulder County with the Urban Drainage and Flood Control District matching on an equal basis the funding of both communities. Special acknowledgement is made to the advisory committee that provided valuable guidance and technical input. Members of the committee were: Mike Serlett, Boulder County Warren Williams, City of Lafayette Ben Urbonas, Urban Drainage and Flood Control District The document is based on the draft storm drainage criteria for Adams County. These draft criteria were modified for the specific conditions and need in the Lafayette-Boulder County area. The consultants, Camp Dresser & McKee, Inc. and the advisory committee wish to acknowledge Adams County for the use of its draft criteria (reformatted to Word document incorporating Amendment No. 1, May 1982) and NPDES Phase 2 regulations, November 1994. 1501. Minimum Design Criteria 1501.1. General Except where specified elsewhere in these specifications, the procedures, criteria and standards set forth in the current Urban Storm Drainage Criteria Manual published by the Urban Drainage and Flood Control District will be utilized to determine the adequacy of any storm drainage plan submitted for approval. It is therefore recommended that the Urban Storm Drainage Criteria Manual be used as a guide in designing the storm drainage system whenever these specifications do not provide specific guidance. 1501.2. Analysis and Acceptable Methods Analysis and determination of the amount of flow at various points in the drainage system shall be made by approved systematic and comprehensive methods. The ---PAGE BREAK--- STANDARDS AND SPECIFICATIONS SECTION 1500 STORM DRAINAGE DESIGN AND TECHNICAL CRITERIA PAGE 3 following methods shall be used to verify the adequacy of designs submitted for approval: a. Rational Method b. Colorado Urban Hydrograph Procedure or c. Other methods as approved by City Council or its designated representative. 1501.3. Design Methods Various methods are available for the analysis and design of drainage systems. The methods described in this section are some of the most common and, if used, shall conform to the limitations included herein. For any method used, the rainfall intensity and total rainfall depths for the selected design storm frequency shall be determined from the Time-Intensity-Frequency Curves provided in Figure 1500-1 or Table 1500-3 in Section 1502.3. 1501.4. Colorado Urban Hydrograph Procedure (CHUP) This method is sufficiently described in detail in the Urban Storm Drainage Criteria Manual and is particularly applicable for complex drainage basins or for areas in excess of 200 acres. The following limitations shall apply to the use of the Colorado Urban Hydrograph Procedure: a. Depression and detention values for various land covers shall conform to the recommended values listed in Table 2 of the Runoff part, Urban Storm Drainage Criteria Manual. b. Unless justified by multiple field infiltration tests, the following infiltration rates of Table 1500-1 are recommended for use with the design storms contained in these specifications. TABLE 1500-1. INFILTRATION LOSSES First 40 minutes of storm: Time (Minutes) Infiltration Loss (Inches) 5 0.20 10 0.13 15 0.10 20 0.07 25 0.06 30 0.05 35 0.05 40 0.05 Remainder of storm Each additional 5 minutes 0.04 c. For the design location, the rainfall time interval selected shall be no more than five minutes for basins smaller than one square mile and no more than ten minutes ---PAGE BREAK--- STANDARDS AND SPECIFICATIONS SECTION 1500 STORM DRAINAGE DESIGN AND TECHNICAL CRITERIA PAGE 4 for large basins. For the purpose of these specifications, areas of one square mile or less are defined as small basins. Figure 1500-1 0 1 2 3 4 5 6 7 8 9 10 0 20 40 60 80 100 120 Time of Concentration (minutes) Rainfall Intensity (in/hr) 2 year 5 year 10 year 50 year 100 year 100 Year 2 Year ---PAGE BREAK--- STANDARDS AND SPECIFICATIONS SECTION 1500 STORM DRAINAGE DESIGN AND TECHNICAL CRITERIA PAGE 5 1501.5. Rational Method This method is described in the Runoff part of the Urban Storm Drainage Criteria Manual and is applicable for small urban areas of less than 200 acres in size. The following limitations shall apply to the Rational Method: a. Maximum initial time of concentration of 10 minutes. b. Time of concentration equal to sum of initial time and average gutter/pipe flow time. c. The runoff coefficients which account for antecedent precipitation corrections, shall be those listed in Table 1500-4. Use of frequency correction factors is not necessary with these coefficients. 1501.6. Criteria for Storm-Flow Analysis The following criteria shall be utilized in the analysis of the drainage system: a. Runoff analysis shall be based upon proposed land use and shall take into consideration all contributing runoff from areas outside of the study area. The analysis of storm runoff from existing developed areas lying outside the study area shall be based upon present land use and topographic features. Drainage reports for off-site developed areas, if available, shall be reviewed for proper coordination of drainage facilities. All undeveloped land lying outside the study area shall be considered fully developed based upon the most probable anticipated future land use. However, whenever the future land use of a specific undeveloped area cannot be accurately predicted, the average runoff coefficient to be used in said area shall not be less than specified for “Business-Neighborhood Areas,” as defined in Table 1500-4. b. The probable future flow patterns in undeveloped areas shall be based on the adopted Comprehensive Plan and associated street plans or future topographic features of planned changes in the land use. c. Average land slopes in both developed and undeveloped areas may be used in computing runoff. However, for areas in which drainage patterns and slopes are established, actual slopes shall be used. d. Flows and velocities that may occur at a design point when the upstream area is fully developed shall be considered. As set forth in Section 1502.7 below, drainage facilities shall be so designed that flows and velocities will not cause erosion damage. e. Streets shall not be used as floodways. Streets may be used to convey local drainage only in accordance with the limitations set forth in Section 1502.10. The primary use of streets shall be for the conveyance of traffic, and all flows exceeding set limitations shall be conveyed by a major storm drainage system. ---PAGE BREAK--- STANDARDS AND SPECIFICATIONS SECTION 1500 STORM DRAINAGE DESIGN AND TECHNICAL CRITERIA PAGE 6 f. The use of natural drainageways is recommended. Channel encroachments or relocations must be justified by thorough analysis of the effects on adjacent developments. g. The planning and design of drainage systems shall be such that problems are not transferred from one location to another. Outfall points shall be designed in a manner that will not create flooding hazards Irrigation ditches shall not be used as outfall points. h. Floodplain information will be required on all preliminary and final drainage plans and shall be in accordance with City of Lafayette or Boulder County Floodplain regulations, as appropriate. i. Where a Major Drainageway Plan or a Flood Hazard Area Delineation (FHAD) report for the City and County is available, or a FHAD is developed under provision 1501.1 of these regulations, the flow routing for both the initial storm and major storm runoff shall conform to said plan. Drainage easements and/or rights-of-way conforming to the master plan report will be required and shall be designated on all drainage plans and subdivision plats. j. Approval will not be made for any proposed building or construction of any structure, including retaining walls, fences, etc., that will encroach into the high hazard area of the 100-year floodplain or any dedicated drainage or utility easements. 1501.7. Detention Pond Design The City of Lafayette’s policy is to require on-site detention for all new development and any redevelopment. The required minimum detention volume and maximum release rates at these volumes for the 10-year and 100-year recurrence interval storm shall be determined in accordance with the procedure and data set forth in the following paragraphs. 1501.7.1. Detention Requirements The minimum required volumes and the maximum release rates at the ponding depths corresponding to the volumes shall be determined using the following equations: Minimum Detention Volume: V = KA (Equation 1501a) For the 100-year, (Equation 1501b) K100 = (1.78I – 0.002I2 – 3.56)/1000 For the 10-year, (Equation 1501c) K10 = (0.95I – 1.90)/1000 ---PAGE BREAK--- STANDARDS AND SPECIFICATIONS SECTION 1500 STORM DRAINAGE DESIGN AND TECHNICAL CRITERIA PAGE 7 Where V = Required volume for the 100- or 10-year storm (acre feet) I = Developed basin imperviousness A = Area (acres) Maximum Release Rates Q100 Q = 1.00A (Equation 1501d) 10 Where Q = 0.24A (Equation 1501e) 100, Q10 A = Area (acres) = release rates for the 100- and 10-year storms respectively (cfs) 1501.7.2. Detention Computation Example Given: 100 acres of land to be developed into a multi-unit (detached) residential community having 50% impervious area. 100-year case (using equations 1501a, b and d) Minimum volume V100 Maximum release rate Q = 0.080A = 8.0 acre feet 100 = (1.0)A = 100 cfs 10-year case (using equations 1501a, c and e) Minimum volume V10 Maximum release rate Q = 0.046A = 4.6 acre feet 10 1501.7.3. Detention Pond Outlet Configuration (Figure 1500-3) = (0.24)A = 24 cfs Presented on Drawings 1500-2 and 1500-3 are two examples for detention pond outlet configurations. Type 1 outlet consists of a grated drop inlet, outlet pipe and an overflow weir in the pond embankment. The control for the 10-year discharge shall be at the throat of the outlet pipe under the head of water as defined in Figure 1500-3. The grate must be designed to pass the 10-year flow with a minimum of 50% blockage twice the 10- year flow). Since the minimum size of the outlet pipe is 18 inches, a control orifice plate at the entrance to the pipe may be required to control the discharge to the design flow. The difference between the 100-year and 10-year discharge is released by the overflow weir or spillway. The surcharge on the outlet pipe shall be included in the total discharge when sizing the overflow weir or spillway. If sufficient pond depth is available, the drop inlet and the grate can be replaced by a depressed inlet with a headwall and trash rack. Depression of the inlet is required to reduce nuisance backup of flow into the pond during trickle flows. Type 2 outlet consists of a drop inlet with an orifice controlled inlet for the 10-year discharge and a crest overflow and pipe inlet control for the 100-year discharge. The control for the 10-year discharge occurs at the orifice opening for the head as shown on the Figure 2.01. The control for the 100-year discharge occurs at the throat of the outlet pipe as shown on Figure 2.01. However, the difference between the 100-year and 10-year discharge must pass over the weir; therefore, the weir must be of adequate length. The effective weir length occurs for three sides of the box less the effect of end contractions. ---PAGE BREAK--- STANDARDS AND SPECIFICATIONS SECTION 1500 STORM DRAINAGE DESIGN AND TECHNICAL CRITERIA PAGE 8 The contraction shall be accounted for by reducing the effective L by 0.4 H, where H is the head of the weir in feet. To insure the 100-year control occurs at the throat of the outlet pipe, a 50% increase in the required weir length is recommended. In addition, the outlet pipe must have an adequate slope to insure throat control in the pipe. 1501.7.4. Trickle Flow Control in Detention Areas The trickle flows through all detention ponds shall be controlled using concrete trickle channels. Refer to Section 1502.7(f) for capacity requirements for trickle channels. The minimum design flow for trickle channels shall be 1.0 cfs. Alternate design can provide underdrain with soft channels. 1501.7.5. Detention Pond Grading Requirements Earthen slopes shall not be steeper than 4H to 1V and flatter slopes are preferred. All earthen slopes shall be covered with top soil and revegetated with grass. When properly landscaped, a detention pond area can be an attractive part of a development, and therefore, landscaping of the detention area is encouraged. Maximum detention pond water depths are determined by the minimum width of the 100- year detention pool according to the table below: Minimum Width Maximum Depth 0 to 100 ft 3.0 ft 101 to 150 ft 3.5 ft 151 to 200 ft 4.0 ft 201+ ft 4.5 ft 1501.7.6. Detention Pond Embankment Protection Whenever a detention pond uses an embankment to contain water, the embankment shall be protected from catastrophic failure due to overtopping. Overtopping can occur when the pond outlets become obstructed or when a larger than a 100-year storm occurs. Failure protection for the embankment may be provided in the form of a buried heavy riprap layer (Class H in the USDCM) on the entire face of the embankment or an emergency spillway having a minimum capacity of twice the maximum release rate for the 100-year storm. Structures shall not be permitted in the path of the emergency spillway or overflow. Also, all requirements of the State Engineer, if any, shall be met during the design and construction. 1502. Design Standards 1502.1. Initial and Major Design Storm Every urban and rural area has two separate and distinct drainage systems. One is the initial system corresponding to the initial (or ordinary) storm recurring at regular intervals. The other is the major system corresponding to the major (or extraordinary) storm which is unlikely to occur more often than once in 100 or more years. Since the effects and routing of storm waters for the major storm may not be the same as for the ---PAGE BREAK--- STANDARDS AND SPECIFICATIONS SECTION 1500 STORM DRAINAGE DESIGN AND TECHNICAL CRITERIA PAGE 9 Figure 1500-2 Housing Density vs. Impervious Area - % 0 5 10 15 20 25 30 35 40 45 50 0 1 2 3 4 5 6 Units/Acre % Impervious ---PAGE BREAK--- STANDARDS AND SPECIFICATIONS SECTION 1500 STORM DRAINAGE DESIGN AND TECHNICAL CRITERIA PAGE 10 initial storm, all storm drainage plans submitted for approval shall be submitted in detail in two separate phases: one indicating the effects of the initial storm and the other showing the effects of the major storm. 1502.1.1. Initial Storm Provisions The initial storm drainage system shall be so designed as to provide protection against regularly recurring damage, to reduce street maintenance costs and traffic hazards, and to provide convenience to residents. Drainage systems consisting of curb and gutter, storm drainage lines, culverts, natural drainageways and other required appurtenances shall be considered a part of the initial storm drainage system. 1502.1.2. Major Storm Provisions The major storm drainage system shall be so designed as to prevent property damage or loss of life from storm runoff expected from a major storm. The effects of the major storm on the initial drainage system shall be stated in the drainage report. 1502.2. Design Storm Frequencies The initial and major design storms shall have not less than the following return period frequencies (unless specified otherwise by a drainage study). TABLE 1500-2. DESIGN STORM FREQUENCIES Land Use or Zoning Design Storm Return Period Initial System Major System Residential/Open Space Areas 2-year 100-year PUD Residential 2-year 100-year PUD Business 5-year 100-year Public Building Area 5-year 100-year High Value General Commercial & Business Areas 5-year 100-year Parks, Greenbelts, etc. 100-year Open Channels and Major Drainageways 100-year Detention & Retention Ponds 2-year 100-year 1502.3. Rainfall Intensities and Design Storms The rainfall intensities to be used in the Rational Method shall be obtained from Figure 1500-1, Time-Intensity-Frequency Curves, for the City of Lafayette, Colorado, contained in these specifications. The five-minute increment, two-hour duration design storms to be used with the Colorado Urban Hydrograph procedure are tabulated in Table 1500-3 of these regulations. Any required rainfall data not provided in these criteria shall be taken from NOAA, Atlas 2, Precipitation – Frequency Atlas of the Western United States, Volume III – Colorado. ---PAGE BREAK--- STANDARDS AND SPECIFICATIONS SECTION 1500 STORM DRAINAGE DESIGN AND TECHNICAL CRITERIA PAGE 11 TABLE 1500-3. 5-MINUTE INCREMENT, 2-HOUR DURATION DESIGN STORMS For use with the Colorado Urban Hydrograph Procedure Time (minutes) Incremental Rainfall Depth/Return Period 2 Year 5 Year 10 Year 100 Year 5 0.01 0.01 0.02 0.03 10 0.03 0.04 0.05 0.05 15 0.07 0.10 0.12 0.11 20 0.14 0.20 0.24 0.22 25 0.24 0.36 0.43 0.41 30 0.14 0.18 0.19 0.68 35 0.07 0.10 0.12 0.38 40 0.04 0.06 0.07 0.22 45 0.04 0.06 0.07 0.14 50 0.03 0.04 0.05 0.14 55 0.03 0.04 0.05 0.11 60 0.03 0.04 0.05 0.11 65 0.02 0.03 0.03 0.11 70 0.02 0.03 0.03 0.05 75 0.02 0.03 0.03 0.05 80 0.02 0.03 0.03 0.05 85 0.02 0.03 0.03 0.05 90 0.01 0.01 0.03 0.05 95 0.01 0.01 0.02 0.03 100 0.01 0.01 0.02 0.03 105 0.01 0.01 0.02 0.03 110 0.01 0.01 0.02 0.03 115 0.01 0.01 0.02 0.03 120 0.01 0.01 0.02 0.03 Total 1.04 1.45 1.76 3.14 Reference: Urban Drainage and Flood Control District Preliminary Design Storm Procedure, Hydrology Research Program, August 1979 1502.4. Runoff Computation Total storm water runoff shall be computed using the hydrologic methods set forth in Section 1501.2 above. Runoff computations for both the initial storm and the major storm shall be submitted with the proposed storm drainage plan. Computations shall be submitted on forms similar to those included in these specifications. The Rational Method shall not be used to compute storm runoff for areas in excess of 200 acres or for complex drainage basins. Larger basins shall be analyzed using the Colorado Urban Hydrograph Procedure or other appropriate hydrograph methods as approved by the City Council or its designated representative. 1502.5. Runoff Coefficients The runoff coefficients to be used in conjunction with the Rational Method shall be those listed in Table 1500-4. As an alternative to said coefficients or for areas not ---PAGE BREAK--- STANDARDS AND SPECIFICATIONS SECTION 1500 STORM DRAINAGE DESIGN AND TECHNICAL CRITERIA PAGE 12 specifically listed in Table 1500-4 (Planned Building Groups, Shopping Centers, Trailer Parks, etc.), a composite runoff coefficient base on the percentage of the different types of surfaces involved may be calculated using the coefficients listed in Table 1500-5. TABLE 1500-4. RECOMMENDED RUNOFF COEFFICIENTS AND PERCENT IMPERVIOUS Land Use or Surface Characteristics Percent Impervious Frequency 2 5 10 100 Business: Commercial Areas 95 0.87 0.87 0.88 0.89 Neighborhood Areas 70 0.60 0.65 0.70 0.80 Residential: Single-Family * 0.40 0.45 0.50 0.60 Multi-Unit (detached) 50 0.45 0.50 0.60 0.70 Multi-Unit (attached) 70 0.60 0.65 0.70 0.80 ½ Acre Lot or Larger * 0.30 0.35 0.40 0.60 Apartments 70 0.65 0.70 0.70 0.80 Industrial: Light Areas 80 0.71 0.72 0.76 0.82 Heavy Acres 90 0.80 0.80 0.85 0.90 Parks, Cemeteries 7 0.10 0.10 0.35 0.60 Playgrounds 13 0.15 0.25 0.35 0.65 Schools 50 0.45 0.50 0.60 0.70 Railroad Yard Areas 40 0.40 0.45 0.50 0.60 Undeveloped areas: Historic Flow Analysis – Greenbelts, Agricultural 2 (See lawns) Offsite Flow Analysis (when land use not defined) 45 0.43 0.47 0.55 0.65 Streets: Paved 100 0.87 0.88 0.90 0.93 Gravel 13 0.15 0.25 0.35 0.65 Drives and Walks 96 0.87 0.87 0.88 0.89 Roofs 90 0.80 0.85 0.90 0.90 Lawns, Sandy Soil 0 0.00 0.01 0.05 0.20 Lawns, Clayey Soil 0 0.05 0.10 0.20 0.40 Note: These Rational Formula coefficients may not be valid for large basins. * % impervious based on density. See Figure 1500-2. Above Percent Impervious shall NOT be used for detention volume calculations. Actual site data must be applied in the appropriate equations. ---PAGE BREAK--- STANDARDS AND SPECIFICATIONS SECTION 1500 STORM DRAINAGE DESIGN AND TECHNICAL CRITERIA PAGE 13 TABLE 1500-5. RUNOFF COEFFICIENTS FOR COMPOSITE ANALYSIS (Rational Method) Surface Type 2 5 10 100 Paved Streets 0.87 0.88 0.90 0.93 Gravel Streets 0.15 0.15 0.15 0.15 Drives and Walks 0.85 0.87 0.90 0.92 Roofs 0.80 0.85 0.90 0.90 Lawns, Sandy Soil 0.00 0.10 0.20 0.50 Lawns, Heavy Soil 0.10 0.20 0.30 0.60 The composite runoff coefficient (Cc ) shall be calculated using C = ∑ Ci A A i Where C = composite runoff coefficient t Ci A = individual runoff coefficient i A = area of each different type of surface to be considered t i = number of different types of surfaces to be considered = total drainage area involved for which the composite coefficient is applicable The Rational Method Formula for use with the initial and major storms shall be defined as: Q = CIA Where Q = storm flow (cfs) I = rainfall intensity (in/hr) from Figure 1500-1 A = drainage area (acres) C = runoff coefficient from Tables 1500-4 or 1500-5 1502.6. Time of Concentration The time of concentration to be used in conjunction with the Rational Method and the Time-Intensity-Frequency Curves of Figure 1500-1 shall be calculated using the following procedure and equations: Tc = Ti + Tf Where Tc = time of concentration (minutes) Ti = initial time of concentration to first design point (minutes) Tf = average flow time to design points (minutes) For urbanized conditions after development), the initial time of concentration shall be calculated using the lesser value obtained from the following two equations: Ti = L 180 + 10 ---PAGE BREAK--- STANDARDS AND SPECIFICATIONS SECTION 1500 STORM DRAINAGE DESIGN AND TECHNICAL CRITERIA PAGE 14 Where L = length along flow line (feet) or Ti = 1.8(1.1 – C5)√L 3 Where C √S 5 S = drainageway slope in percent = runoff coefficient for a 5-year storm Under no circumstances shall the initial time of concentration used in drainage studies be less than 5 minutes. If the use of Equation above results in less than 5 minutes, use 5 minutes for the initial time of concentration. For non-urbanized conditions, Equation above shall be used to calculate initial time of concentrations for values of L less than 500 feet. For overland flow in excess of 500 feet, the user shall calculate the time of concentration using Equation using the values for average flow time plus the initial time of concentration from Equation with L less than 500 feet. 1502.7. Open Channels Except as modified herein or required by Lafayette/Boulder County drainageway master plan, major drainageway open channels shall be designed for the 100-year frequency storm and shall conform to the criteria set forth in the Major Drainage part of the Urban Storm Drainage Criteria Manual. However, the channel design shall also be analyzed with respect to initial storm runoff and its effects made known. Particular attention shall be given to channel scour, erosion and sedimentation for the initial design storm and trickle flows. Whenever practical, the channel should have slow flow characteristics, be wide and shallow, and be natural in its appearance and function. All major drainageway channels shall be designed for UDFCD maintenance eligibility. Grass-lined channels shall be designed not to exceed maximum scour velocities for the type of soil and vegetative cover, so that in no case the velocities shall result in a Froude Number (turbulence factor) in excess of 0.8. Channel capacities should be computed from Manning’s Formula for uniform flow after accounting for all backwater effects of street crossings, diversion structures, drop structures, contractions, expansions and other control structures that affect flow depth. Channel depths should avoid critical or super critical flow. Water surface profiles and flood plain delineations will be required for all water surface drainageways where the 100-year flow rate is greater than 100 cubic feet per second. The channel cross section may be almost any type suitable to the location. However, the limitations for design for the major storm and initial storm design flows shall include: a. Side Slopes - Side slopes for grassed channels shall be as flat as practical. Side slopes shall be no steeper than 4:1. Under special conditions in already developed ---PAGE BREAK--- STANDARDS AND SPECIFICATIONS SECTION 1500 STORM DRAINAGE DESIGN AND TECHNICAL CRITERIA PAGE 15 areas and when approved in writing by the City Council or its designated representative, slopes of 3:1 may be utilized. In lined channels where side slopes are steeper than 3:1 full security fencing shall be provided. Other safety measures may be required by the City Council or its designated representative. Only concrete lined channels will be permitted to have side slopes steeper than 3:1. b. Depth - the maximum design depth of flow (outside trickle channel area) for the major storm should be limited to depths of 4.0 to 5.0 feet in grass lined channels. The minimum bottom width shall be calculated using the maximum depth. Critical depths shall be investigated for both the major and initial storm runoffs and these values made known. c. Freeboard - Except where localized overflow in a certain area is desirable for additional ponding benefits or other reasons, the minimum allowable freeboard in feet shall be V2/2g+0.5 (where V=average velocity and g=32.2 ft/sec2 ) with a minimum of 1 foot and maximum of 3.5 feet. d. Slope of Channel - Grass-lined channels normally will have slopes of 0.2 to 0.6%. Where the natural topography is steeper than desirable, drops shall be used to control design velocities. e. Curvature - Generally, the center line curvature shall not have a radius less than twice the design flow top width, but not less than 100 feet. f. Trickle Channels - Concrete-lined trickle channels to carry low flows will be required for all urban grassed channels. The capacity of a trickle channel should be a minimum of 1.0% of the 100-year design flow. Under-drain pipes may be used for trickle flow, but the diameter shall be a minimum of 24 inches and shall be sloped to provide a minimum velocity of 3 feet per second when flowing half full. g. Design Velocity - The maximum velocity for the major storm design runoff shall not exceed 7.0 feet per second for unlined channels, except in sandy soil where the maximum velocity shall not exceed 5.0 feet per second. Froude Number (turbulence factor) shall be less than 0.8 for grass-lined channels. Channels having a Froude Number greater than 0.8 shall be lined with continuously (two- way) reinforced concrete liner. Unless shown to be unachievable, the minimum velocity shall not be less than 2.0 feet per second for the initial storm runoff. h. Roughness Coefficient – The values for Manning’s n shall not be less than those specified in Section 1500.3 below. i. Erosion - All channels shall be designed with proper and adequate erosion control features. Particular attention shall be paid at all storm inflow areas, where rundowns shall be provided. j. Water Surface Profiles - A water surface profile for the major storm runoff shall be computed and clearly shown on the final drawings submitted for approval. Computations of the water surface profile should utilize standard backwater ---PAGE BREAK--- STANDARDS AND SPECIFICATIONS SECTION 1500 STORM DRAINAGE DESIGN AND TECHNICAL CRITERIA PAGE 16 methods, taking into consideration all losses due to velocity changes, drops, bridge and culvert openings, and other obstructions. Computations shall be submitted with the final design plan. Whether or not the energy gradient line is shown on the final drawings is optional. k. Maintenance Access - Access shall be provided to all major drainageway channels for maintenance purposes, and additional easements or rights-of-way shall be dedicated, if necessary, in order to insure access to the channel. Maintenance roads shall be required along any open channel utilized for major storm drainage. Such roadways must be approved by the City Council or its designated representative before approval of the drainage system final drawings. 1502.8. Irrigation Ditches Irrigation ditches shall not be used to transmit storm runoff unless such use is shown by thorough hydraulic engineering analysis to be without hazard. Such analysis shall include investigation of the residual ditch capacity after maximum irrigation flow and other storm drainage has been deducted. A letter of authorization, signed and dated by an authorized officer or representative of the owner of the ditch, shall be submitted for any contemplated use or modification of irrigation ditches for storm runoff. 1502.9. Storm Drainage Lines and Storm Inlets Except as subsequently modified, the design of storm drainage lines and storm inlets shall conform to the criteria set forth in the Urban Storm Drainage Criteria Manual. Storm drainage lines and inlets shall be of sufficient capacity to adequately carry the expected runoff from the initial design storm. The storm drainage system and subsequent storm inlets shall commence at all locations where the allowable street capacity is exceeded (Section 1502.11) or wherever ponding of water is likely to occur. No bubblers will be allowed. 1502.9.1. Storm Drainage Lines The minimum allowable pipe size to be used in storm drainage lines and laterals shall be as listed in Table 1500-6. Arch or eliptical pipes will be allowed where design conditions dictate, provided, however, the minimum cross-sectional areas shall not be less than those specified. All storm water conduits and appurtenances shall be of sufficient structural strength to withstand an H-20 design load. TABLE 1500-6. MINIMUM ALLOWABLE PIPE SIZE Type of Conduit Minimum Pipe Diameter Minimum Cross- Sectional Area Main trunk storm water lines Reinforced concrete pipe or VCP 18-inch 1.77 sq. ft. Individual Storm water line Laterals Reinforced concrete or VCP 15-inch 1.23 sq. ft. ---PAGE BREAK--- STANDARDS AND SPECIFICATIONS SECTION 1500 STORM DRAINAGE DESIGN AND TECHNICAL CRITERIA PAGE 17 The maximum allowable distance between manholes or other suitable appurtenances for cleanouts shall not exceed those listed in Table 1500-7. Manholes shall be located at every change in alignment or grade of the storm drainage line. TABLE 1500-7. MAXIMUM ALLOWABLE MANHOLE SPACING Inside Diameter or Minimum Head Room Maximum Allowable Distance between Manholes and Cleanouts 15 inch to 30 inch 400 ft. 36 inch and larger 500 ft. The capacities of conduits shall be computed using Manning’s formula or appropriate flow nomographs. The value of the roughness coefficient to be used shall not be less than those specified in Section 1503.2 below. The average full-flow velocity in conduits shall not be less than 2.0 feet per second. 1502.9.2. Storm Inlets Allowable storm inlets shall be opening inlets equal to CDOT Type R. Curb opening inlets shall be utilized at all points where ponding or sump conditions exist in streets or where the street capacity is exceeded. CDOT Type 13 inlets may be used in swales. Inlets close to residential areas shall have close mesh grates. The theoretical capacity and spacing of storm inlets will be analyzed using Figures A2 through A4 of these criteria for curb opening inlets on continuous grade. The allowable inlet capacity will be determined using the reduction factors listed in Table 1500-8. These reduction factors compensate for debris plugging, pavement overlaying, variations in design assumptions or other factors which decrease inlet capacities. TABLE 1500-8. INLET REDUCTION FACTORS Condition Inlet Type % of Theoretical Capacity Allowed Sump and grate Combination 65% Curb opening only 80% Grate only 50% The size of outlet pipes from storm water catch basins shall be based upon the theoretical capacity of the inlet, but shall not be less than 15 inches in diameter for R.C.P. Computations for storm drainage design and storm inlet designs shall be submitted for approval on forms similar to those included in these specifications (Appendix Adequate details of the proposed storm drainage system, including plan and profile, details of inlets, manholes and other appurtenances, shall be included in the overall drainage plan submitted for approval. ---PAGE BREAK--- STANDARDS AND SPECIFICATIONS SECTION 1500 STORM DRAINAGE DESIGN AND TECHNICAL CRITERIA PAGE 18 Multiple combination curb/grate inlet installations will not be permitted. Curb opening inlets (modified Type R) shall be used in place of multiple inlet installations. 1502.10. Culverts Culvert capacities shall be at least equal to the capacities of culverts designed in accordance with the procedures outlined in the Bureau of Public Roads, Hydraulic Engineering Circulars No. 5 and 10. Culverts may be of any size and construction as required by existing topographic features; however, the size, shape, location and type of construction of culverts shall be subject to approval. Culvert installations shall be designed with an emergency overflow for the major storm on all streets other than major arterials. Culverts under major arterials shall have sufficient capacity to pass all of the runoff from the major storm considering 20 percent of the inlet plugged. In determining the amount of emergency overflow required, capacity reductions as shown in Table 1500-9 shall apply unless otherwise approved by the City Council or its designated representative. The appropriate amount of emergency overflow onto streets shall be taken into account when analyzing storm runoff and allowable street capacities for the major storm. TABLE 1500-9. CAPACITY REDUCTION FOR STRUCTURES Cross-Sectional Area of Culvert % of Major Storm Flow to be Considered as Overflow Less than 20 sq. ft. 100% 20 sq. ft. and over 20% The following design criteria shall be used for all culvert design: The culvert, including inlet and outlet structures, shall properly take care of stormwater, bed-load, and debris at all stages of flow. a. Inlets - Culvert inlets shall be designed to minimize entrance and friction losses. Inlets shall be provided with either flared-end sections or head walls with wing walls. Projecting ends will not be accepted. For large structures, provisions shall be made to resist possible structural failure due to hydrostatic uplift forces. b. Outlets - Culvert outlets shall be designed to avoid sedimentation, undermining of the culvert, or erosion of the down-stream channel. Outlets shall be provided with either flared-end sections or headwalls with wingwalls. Projecting outlets will not be acceptable. Outlet protection in the form of riprap, channel shaping, etc. is required where scouring discharge velocities occur. c. Slopes - Culvert slopes should be such that neither silting nor excessive velocities and scour occur. Generally, the minimum slope of culverts shall be 0.50%. ---PAGE BREAK--- STANDARDS AND SPECIFICATIONS SECTION 1500 STORM DRAINAGE DESIGN AND TECHNICAL CRITERIA PAGE 19 d. Headwater - Generally, the headwater-to-diameter ratios should not exceed those recommended in Table 1500-10. Excessive ponding above culvert entrances will not be acceptable if such ponding appears likely to cause property or roadway damage, culvert clogging, saturation of fills, detrimental upstream deposits of debris, or inundation of existing or future utilities and structures. TABLE 1500-10. RECOMENDED MAXIMUM HW/D RATIOS Storm Frequency HW/D Less than or equal to 10-year 1.0 100-year 1.5 e. Tailwater - The height of tailwater at the outlet shall be subject to the criteria set forth in Section 1502.10(d) above. f. Hydraulic Design - Culverts shall be analyzed to determine whether discharge is controlled by inlet or outlet conditions for both the initial storm discharge and the major storm discharge. The value of the roughness coefficient used shall not be less than those specified in Section 1503 below. Computations for selected culvert sizes shall be submitted for approval on forms similar to those included in these specifications. g. Minimum Allowable Size - The required size of the culvert shall be based upon adequate hydraulic design analysis. In no case, however, will approval be made for round culverts with less than 24 inches inside diameter or for arched or oval- shaped culverts with rise-span dimensions less than 18 inches x 28 inches nominal. h. Multiple Culvert Installations - Where physical conditions dictate, multiple culvert installations will be acceptable subject to approval. The minimum size of any culvert to be used shall not be less than the requirements set forth in Section 1502.10(g) above. i. Structural Design - The structural design of culverts shall conform to H-20 loading and shall meet AASHTO “Standard Specifications for Highway Bridge” requirements. Where appropriate the applicable provisions of Section 1502.9 shall also apply to the design of culverts. 1502.11. Street Flow Capacities Except as modified herein, the criteria set forth in the Urban Storm Drainage Criteria Manual will be used in analyzing and approving the adequacy of streets as a function of the drainage system. Both the initial storm runoff and major storm runoff must be considered, and calculations showing such runoff at critical sections shall be submitted. The following criteria shall apply in the determination of allowable street flow capacities: ---PAGE BREAK--- STANDARDS AND SPECIFICATIONS SECTION 1500 STORM DRAINAGE DESIGN AND TECHNICAL CRITERIA PAGE 20 a. Street, curb/gutter, walks, crosspans, inlets and curb cuts shall conform to the latest revision of the Lafayette Standard Specifications for Design and Construction of streets, curb and gutter, and sidewalks. b. Street /Capacity for Initial Storms - Pavement encroachment for the initial storm shall not exceed limitations set forth in Table 1500-11 as corrected by an appropriate reduction factor. TABLE 1500-11. ALLOWABLE PAVEMENT ENCROACHMENT AND DEPTH OF FLOW FOR INITIAL STORM RUNOFF Street Classification Maximum Encroachment* Local No curb overtopping. Flow may spread to crown of street. Collector No curb overtopping. Flow spread must leave the equivalent of one 10-foot driving lane clear of water. Major & Minor Arterials No curb overtopping. Flow spread must leave the equivalent of two 10-foot driving lanes clear of water, one lane in each direction. Principal Arterial No encroachment is allowed on any traffic lane. *Where no curbing exists, encroachment shall not extend past property lines. The storm drainage system shall begin at the point where the maximum allowable encroachment occurs or at the point where the curb capacity is exceeded, as estimated by the procedures outlined in Appendix A of this manual, whichever occurs first. An example curb capacity calculation is included in Appendix A. c. Street Capacity for Major Storm – The allowable depth of flow and inundated area for the major design storm shall not exceed the limitations set forth in Table 1500-12. TABLE 1500-12. ALLOWABLE DEPTH OF FLOW FOR MAJOR STORM RUNOFF Street Classification Allowable Depth and Inundated Areas Local and Collector Residential dwellings, public, commercial and industrial buildings shall not be inundated at the ground line unless buildings are flood-proofed. The depth of water over the gutter flowline shall not exceed 18 inches. Arterials Residential dwellings, public, commercial and industrial buildings shall not be inundated at the ground line unless buildings are flood-proofed. Depth of water at the street crown shall not exceed 6 inches to allow operation of emergency vehicles. The depth of water over the gutter flowline shall not exceed 18 inches. d. Cross Street Flow – Cross street flow can occur by two separate means. One is runoff that has been flowing in a gutter and then flows across the street to the opposite gutter or inlet. The second case is if flow from some external source, ---PAGE BREAK--- STANDARDS AND SPECIFICATIONS SECTION 1500 STORM DRAINAGE DESIGN AND TECHNICAL CRITERIA PAGE 21 such as a drainageway or conduit, that will flow across the crown of the street when the conduit capacity is exceeded. The maximum allowable cross street flow depth based on the worst conditions shall not exceed the limitations stipulated in Table 1500-13. TABLE 1500-13. ALLOWABLE CROSS STREET FLOW Street Classification Initial Design Storm Runoff Major Storm Runoff Local 6-inch depth in crosspan with no overtopping at the crown 18 inches of depth above gutter flowline Collector Where crosspans are allowed, depth of flow shall not exceed 6 inches. No crown overtopping shall be permitted. 18 inches of depth above gutter flowline Arterial None 6 inches or less over crown. e. Capacity Calculations – All theoretical street flow capacities based on Section 1502.11(b) shall be reduced by the appropriate reduction factors to obtain allowable street flow capacities. Reduction factors shall be as indicated in Figure 1500-3 for local and collector streets and Figure 1500-4 for arterial streets. ---PAGE BREAK--- STANDARDS AND SPECIFICATIONS SECTION 1500 STORM DRAINAGE DESIGN AND TECHNICAL CRITERIA PAGE 22 Figure 1500-3 ---PAGE BREAK--- STANDARDS AND SPECIFICATIONS SECTION 1500 STORM DRAINAGE DESIGN AND TECHNICAL CRITERIA PAGE 23 1503. Design Aids 1503.1. General The design data, forms, standards and other information presented in this section are included as design aids for the engineer. All data included herein shall be considered as minimum design criteria unless specified otherwise and will be used to determine the adequacy of any storm drainage submitted for approval. 1503.2. Roughness Coeffcient The value of the roughness to be used in Manning’s Formula shall not be less than those listed in Table 1500-14. ---PAGE BREAK--- STANDARDS AND SPECIFICATIONS SECTION 1500 STORM DRAINAGE DESIGN AND TECHNICAL CRITERIA PAGE 24 TABLE 1500-14. MINIMUM VALUES OF ROUGHNESS COEFFICIENT Manmade Drainageways Closed Conduits Minimum n Concrete Pipe Culverts with bends, connections & some debris 0.013 Storm Drainage Lines 0.013. Subdrain with open joints 0.016. Corrugated Metal Pipe Culverts (per CSPL recommendation) 0.014 – 0.024. Structural plate 0.034 Lined Channels Concrete surface (bottom and sides): Smooth Finish 0.015 Unfinished 0.017 Curb and gutter 0.021 Concrete bottom with sides of: Mortared stone 0.020 Dry rubble or riprap 0.030 Gravel bottom with sides of: Formed concrete 0.020 Dry rubble or riprap 0.033 Grass-Lined Straight With landscape features 0.030 0.035 1503.3. Design Forms The design forms included herein are: Effective Rainfall Computations (CUHP) SD 1-1 Storm Hydrograph Computations (CUHP) SD 1-2 Runoff Computations (Rational Method) SD 1-3 Standard Culvert Design Form SD 1-4 ---PAGE BREAK--- STANDARDS AND SPECIFICATIONS SECTION 1500 STORM DRAINAGE DESIGN AND TECHNICAL CRITERIA PAGE 25 Subdivision Location Design Storm Yr Recurrence Interval Computations by Submitted by Date Engineering Firm DESIGN FORM SD 1-1 EFFECTIVE RAINFALL COMPUTATIONS (COLORADO URBAN HYDROGRAPH PROCEDURE) Pervious Areas % Impervious Area % Total Average Effective Precipitatio n (in.) Time (min.) Total Precipitat ion (in.) Incremental precipitation (in.) Rearranged Incremental Precipitation (in.) Maximum Infiltration (in.) Detention & Depression Storage (in.) Effective Precipitatio n (in.) Effective Precipitatio n (in.) Detention & Depression Storage (in.) Loss (in.) Effective Precipitatio n (in.) Effective Precipitatio n (in.) (10) (11) (12) (13) ---PAGE BREAK--- STANDARDS AND SPECIFICATIONS SECTION 1500 STORM DRAINAGE DESIGN AND TECHNICAL CRITERIA PAGE 26 Subdivision Location Design Storm Yr Recurrence Interval Computations by Submitted by Date Engineering Firm DESIGN FORM SD 1-2 STORM HYDROGRAPH COMPUTATIONS (COLORADO URBAN HYDROGRAPH PROCEDURE) Time (min.) Unit Hydrograph (cfs) Excess Precipitaion in Inches Storm Hydrograph (cfs) (10) (11) (12) (13) (14) (15) (16) (17) ---PAGE BREAK--- STANDARDS AND SPECIFICATIONS SECTION 1500 STORM DRAINAGE DESIGN AND TECHNICAL CRITERIA PAGE 27 Design Point Area Designation A C Cf c = (CxCf) A•c ΣA•c tc I Q=(ΣA•c)xI Slope Length VEL t Remarks acres min in/hr cfs feet fps min Subdivision Location Computations by Submitted by Engineering Firm DESIGN FORM SD 1-3 RUNOFF COMPUTATIONS (RATIONAL METHOD) ---PAGE BREAK--- STANDARDS AND SPECIFICATIONS SECTION 1500 STORM DRAINAGE DESIGN AND TECHNICAL CRITERIA PAGE 28 HW/D HW Ko H dc 2 TW ho LSo HW Subdivision Location Computations by Submitted by Engineering Firm DESIGN FORM SD 1-4 CULVERT DESIGN FORM Inlet Control Outlet Control HW=H + ho - LSo Headwater Computation Description (Entrance Q or q Size For Outlet Control H.W. = H + ho - L So For TWD ; ho = T.W. For Box Culvert ; dc = 0.315 (Q/B)3/2 ---PAGE BREAK--- ---PAGE BREAK--- ---PAGE BREAK--- ---PAGE BREAK--- ---PAGE BREAK--- ---PAGE BREAK--- ---PAGE BREAK--- ---PAGE BREAK--- ---PAGE BREAK--- ---PAGE BREAK--- ---PAGE BREAK--- ---PAGE BREAK--- ---PAGE BREAK--- ---PAGE BREAK--- MIN)23i I ‘4 ‘4 ‘ ‘7 ‘73 ‘ ‘7 ‘7 ‘74’73 ‘74’73 ‘7 4 ‘3 ‘4 ‘P ‘P ‘ ‘73 ‘7 44 ‘73 ‘74 ‘773 ‘74 ‘73 ‘4 ‘t’’P 3 ‘7t’p ‘73 ‘P ‘P1 3 ‘7373 p343 ‘ø4P3 ‘73’74 N. ‘v ‘73”P3 ‘73 ‘73 ‘7444 ‘P’V ‘p’p 44’ ‘74 ‘73 ‘7 ‘“vj’ 4 ‘P ‘74 P7 4 ’744 44 ‘73 ‘ : : 33:: ,33 N ji.r’’& &‘44 1 4.’7 47’44”7’44’4’fr4r4; 1 44 ‘4’4 ‘ ‘ ‘ - ‘i ‘7 ‘7 ‘ T&’7”i ‘7 . N ED3 N % ‘73;’4 44 .3J.*’1 - ‘1 I2 A 0 . NOTE: EROSION CONTROL MEASURES SHALL BE MAINTAINED AT ALL TIMES AS _L DIRECTED BY THE CITY ENGINEER BALLAST (MIN) SUBGRADE NOTES 1. ALL ROCK TO BE REMOVED UPON COMPLETION OF SECTION A—A CONSTRUCTION. 2. PUBLIC ROADWAY TO BE ‘ KEPT CLEAN AND FREE OF MUD, DIRT AND DEBRI AT ALL TIMES. OWN. CM — ROCK ENG PFJ P11 SCALE SwG No NTS 400—10 11/Or, ---PAGE BREAK--- ---PAGE BREAK--- ---PAGE BREAK--- ---PAGE BREAK--- ---PAGE BREAK--- ---PAGE BREAK--- ---PAGE BREAK--- ---PAGE BREAK--- ---PAGE BREAK--- ---PAGE BREAK--- ---PAGE BREAK--- ---PAGE BREAK--- ---PAGE BREAK--- ---PAGE BREAK--- ---PAGE BREAK--- ---PAGE BREAK--- ---PAGE BREAK--- ---PAGE BREAK--- ---PAGE BREAK--- ---PAGE BREAK--- ---PAGE BREAK--- ---PAGE BREAK--- ---PAGE BREAK--- ---PAGE BREAK--- ---PAGE BREAK--- ---PAGE BREAK--- ---PAGE BREAK--- ---PAGE BREAK--- ---PAGE BREAK--- ---PAGE BREAK--- ---PAGE BREAK--- ---PAGE BREAK--- ---PAGE BREAK---