Specifications include, but are not limited to: 1. Removal of the existing 24” Drainage Pipe a. Contractor shall create two straight lines on the asphalt which shall remain no less than sixteen inches away from any permanent structures. The total width between the two lines shall be five feet. On the downstream side of the drainage pipe there is a twelve by twenty-foot area of the asphalt that is deteriorating, this area must be cut back square. b. Contractor shall utilize sheet piling when the excavation is closer than five feet from the existing buildings to stop any undermining of the existing structures. Any damage to the existing structures created by excavating will be the responsibility of the contractor. Damage to any utilities due to the excavation will be the responsibility of the contractor. c. A repair was made on this 24” Drainage Pipe several years in the past, as a preventative measure concrete was poured on the repair area. The contractor will be responsible for removal of approximately a 108 cubic foot block of concrete before the installation of the new 36” HDPE Bell and Spigot piping. d. Contractor shall cut the asphalt following the straight lines with an abrasive blade that will leave a clean ninety degree cut. e. Contractor shall excavate for the removal of the existing 24” drainage pipe. The trench that is to be excavated will be no less than five feet wide for the installation of the new 36” drain pipe. f. Contractor will be responsible for bypass pumping of the flow coming into the area of excavation. Bypass pumping shall continue for the entirety of this project. g. All removed pipe and excavated spoils become the property of the contractor and must be removed from site. In no way can any of the excavated spoils be reused for any portion of backfilling or compacting. 2. HDPE Corrugated Bell and Spigot Installation a. Contractor shall excavate ten inches deeper than the elevation of the base of the 24” drainage pipe. The base elevation of the new HDPE piping will be four inches deeper than the base elevation of the removed 24” drainage pipe. The remaining six inches will be backfilled with 57 stone for HDPE pipe bedding, see figure 3. b. The contractor will place the HDPE Corrugated Bell and Spigot Piping carefully on the prepared foundation of six inches of 57 stone bedding starting at the downstream end with the inside circumferential laps pointing downstream and with the longitudinal laps at the side of quarter points. c. The contractor will be responsible for supplying and utilizing all coupling bands for the installation of the 36” HDPE Corrugated Bell and Spigot Piping...
