SECTION 5 - STREET CONSTRUCTION AND DESIGN 1. SPECIFICATIONS FOR STREET CONSTRUCTION AND DESIGN All residential subdivision streets built within the unincorporated area of Riley County shall be built so as to comply with the Riley County specifications for crushed stone subgrade and surfacing as stated herein. Equivalent road sections using flyash, geofabrics or lime subgrade treatment based on soil tests and designed by a professional engineer licensed in Kansas may be approved. This specification shall constitute a minimum standard. Higher construction standards may be required by resolution for designated areas as conditions may warrant. All paved streets in residential subdivisions shall be built so as to comply with the "Riley County Kansas Standard Specifications for the Construction of Paving, Storm Sewers, Curb and Gutter, and Sidewalks". Streets in commercial or industrial subdivisions shall be so designed to carry the anticipated loads for each unique situation. 2. INSPECTION AND APPROVAL FOR MAINTENANCE Street projects are constructed at the expense of the subdivision's developer. The Riley County Public Works Department is responsible for inspection of the construction. A final inspection of the project is made and is attended by the developer, County Public Works and township personnel. If the condition of the project is satisfactory, the County Engineer recommends to the County Commission that the streets be accepted and be turned over to the township in which they are located for maintenance. 3. GUARANTEE OF SATSIFACTORY PERFORMANCE a. A developer may construct the streets in a subdivision with or without having posted a performance bond with the County. If the developer elects to post the bond, the final plat of the subdivision may be filed and building permits issued prior to the acceptance of the streets. If the developer elects not to post bond, the subdivision plat may not be filed nor building permits issued until the roads are accepted. The performance bond shall be in the amount of the contract cost of the road improvements. b. In the case where a developer starts a street project without a performance bond and encounters interest from parties interested in obtaining building permits, the developer will be allowed to post a performance bond in the amount of the estimated cost of the remaining work. In no case will a street project be accepted without the developer having posted a maintenance bond for the project. The maintenance bond is in the amount of fifteen percent of the construction cost of the project and is to remain in force for one year after the streets are accepted. Performance and maintenance bonds must be issued by a bonding company registered to do business in the State of Kansas. Letters of credit or cashiers checks will be accepted in lieu of bonds. Personal checks or collateral assignments will not be accepted.
4. CRUSHED STONE SUBGRADE Crushed stone subgrade shall be supplied and installed in accordance with sections 306.01 through 306.03 of the K.D.O.T. Standard Specifications for State Road and Bridge Construction (1990 edition) with the following exceptions: 1. Compaction shall be Type B (MR-90) 2. The Road Mix Method may be used. 3. The gradation requirements for "Crushed Stone for Backfill" shall be as noted below: 5. SURFACING Sieve Size % Retained 3" 0 0.375" 20-50 No. 16 50-100 a. DESCRIPTION This work shall consist of the placing of aggregate for surfacing in a windrow, and the uniform spreading and compaction of the windrowed material in reasonable close conformity with the details displayed in Exhibit I (on display in Riley County Planning & Development Office). The use of a mechanical spreader may be substituted for the windrow-uniform spreading method. b. CONSTRUCTION REQUIREMENTS The aggregate materials to be utilized shall be combined material (AB-3) as described in the K.D.O.T. Specifications for State Road and Bridge Construction. The aggregate material to be utilized shall be approved by the County Engineer. The approved material shall be hauled in suitable vehicles having dump beds suitable for dumping the materials. No hauling of materials will be permitted when in the judgement of the County Engineer, the weather or road conditions are such that hauling operations cause excessive cutting or rutting of the road surface. The materials approved for delivery to the road shall be uniformly distributed through out the length of the road to be improved. The rate of application shall be as shown herein for the various materials provided. Section 5 Street Construction and Design
6. MINIMUM DESIGN STANDARDS Right-of-way... 60' for Service Street... 100' for Minor Trafficways... 120' for Major Trafficways Horizontal Curvature... 300' Rad. for Trafficways... 150' Rad. for Service Streets Sight Distance...150' Roadbed Width...24' Ditch Depth...2' Ditch Width...4' Should Slope... 3:1 Back Slope... 2:1 Bridge Design Loading... AASHTO A-20 Bridge Roadway Width...24' Maximum Roadway Grade...12% These standards may be recommended for waiver by the County Engineer if terrain features and/or safety considerations justify such a waiver. 7. EXTRAORDINARY CONDITIONS Where, in the opinion of the County Engineer, extraordinary pedological conditions are encountered in a subdivision, a special street design may be required. California Bearing Ratio and modified Proctor density curves shall be provided to assist the County Engineer in determining if extraordinary conditions exist. Section 5 Street Construction and Design