8.1. SR 06-03-2019 - Laserfiche WebLink

Home Browse Search

2. For storm sewers and subdrains,all joints shall not permit the intrusion of soil or backfill materials. (a) If reinforced concrete pipe is used,the Contractor may at its own discretion choose to wrap each joint with a geotextile filter fabric,as specified, rather than place mastic in the joint. D. Bulkheading Open Pipe Ends 1. The Contractor shall furnish, install and maintain a temporary,water-tight plug adequately blocked in place to prevent flooding of the existing downstream sewer system. The plug shall be placed at the beginning of the project or at the end of each working day at the end of the day's operation. 2. When flows are diverted from an existing sewer or tile to be abandoned in place,the Contractor shall construct a water-tight plug on the open end of the abandoned pipe. 3. Permanent watertight plugs shall be constructed with concrete grout with a thickness of not less than 1 pipe diameter. 3.3 BEDDING AND BACKFILLING OPERATIONS A. Backfill material around all manholes,catch basins,valve boxes,curb boxes,and hydrants shall be compacted with hand machines. The maximum lift thickness shall be 6-inches. B. Flexible Pipe Materials 1. Unless otherwise shown on the plans,the pipe shall be bedded and backfilled with granular material compacted to 95 percent Standard Proctor Density or as recommended by the pipe manufacturer, whichever is denser,from 6.0-inches below the bottom of the pipe to 12.0-inches above the top of the pipe the full width of the trench. The Contractor shall bed and backfill the pipe as shown on the plan details. 2. Where the trench foundation has been found to be unstable and not suitable for bedding,the trench shall be undercut until acceptable conditions are found. The Contractor shall then install compacted foundation material to meet the line and grade specified on the plan. 3. Unless otherwise shown on the plans,select native material may be used as a trench backfill above the granular bedding up to the bottom of the subgrade except in those conditions where the top of the pipe is less than 12-inches from the bottom of the subgrade in which case granular material compacted to 100 percent Standard Proctor Density shall be used as trench backfill the full width of the trench to the bottom of the subgrade excavation zone. C. Rigid Pipe Materials 1. Unless otherwise shown on the plans, in ordinary or stable trench conditions,the bottom of the trench shall be first excavated to a depth of approximately 15 percent of the outside pipe diameter below the established grade for the bottom of the pipe. Then the bottom of the trench shall be further excavated to allow for the placement of 6.0-inches of granular bedding for a width of at least 60 percent of the outside diameter of the pipe. Pipe shall be placed on the bottom of the pre-shaped excavated trench. The bottom of the excavated trench shall be shaped to fit the circumference of the pipe up to 0.15 of the outside diameter of the pipe. The Contractor shall encase the pipe from the 0.15 outside diameter to the 0.60 diameter height of the pipe with granular material compacted to 95 percent Standard Proctor Density or as recommended by the pipe manufacturer,whichever is denser. 2. Where the trench foundation has been found to be unstable and not suitable for bedding,the trench shall be undercut until acceptable conditions are found. The Contractor shall then install compacted foundation material to meet the line and grade specified on the plan. 3. Unless otherwise shown on the plans,select native material may be used as trench backfill above the granular bedding up to the bottom of the subgrade except in those conditions where the top of the pipe is less than 12.0-inches from the bottom of the subgrade in which case granular material compacted to 100 percent Standard proctor Density shall be used as trench backfill the full width of the trench to the bottom of the subgrade excavation zone. D. Structures Elk River Landfill, Inc. -R16.115896 TRENCH EXCAVATION, BEDDING AND BACKFILL March 2019 PAGE 02320-4 V101807©Bolton&Menk,Inc.2018,All Rights Reserved