02-11-1985 Council Packet - Laserfiche WebLink

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The maximum trench width at one (1) foot above the top of the pipe shall be equal to the pipe outside diameter plus 24 inches for pipe 36" in diameter or smaller and shall be equal to the pipe outside diameter plus 36 inches for pipe greater than 36" in diameter. If the trench is excavated to a greater width than that specified in the pre- ceding paragraph, the Engineer may direct the Contractor to provide a higher class of bedding, a higher strength of pipe or both to satisfy the design strength requirement with no additional compensation allowed therefor. 24,000.3.E3. Pipe Foundation and Bedding: Where ordinary bedding is allowed on existing materials, the trench shall have a bottom conforming to the grade to which the pipe is to be laid. The pipe shall be laid upon sound soil, cut true and even so that the barrel of the pipe will have bearing over at least 50 percent of the pipe width for its entire length. Bell holes shall be exca- vated to insure that the pipe rests for its entire length upon the bottom of the trench. The side fills and the area over the pipe to the depth indicated on the sewer bedding detail shall be filled with natural trench material care- fully compacted in place. Where specified, improved bedding shall be achieved by bedding the pipe in compacted crushed rock or angular granular material of which 100 percent passes a 3/8 inch sieve and a maximum of 5 percent passes a #10 sieve. All bedding material, side fills rind the area over the pipe to the depth indicated on the bedding detail shall be carefully compacted in place. All polyvinyl chloride sewer pipe shall he installed and bedded in accordance with ASTM specification D-2321, "Recommended Practice for Underground Instal- lation of Flexible Thermoplastic Sewer Pipe." Bedding regifirements shall in- clude mechanical compaction of sand and gravel material surrounding the pipe to at least ninety-five (95%) percent of maximum density as described in ASTM Methods D698 to prevent deflection of the pipe cross-section. Payment for such bedding and compaction operations shall be considered incidental to the installation of the sewer pipe. Where existing soils are of non -granular nature, the Contractor shall furnish sand or gravel material for pipe bedding as incidental to the cost of the pipe. The Owner reserves the right to measure deflection of PVC sewer pipe 30 days after placement of backfill material in the trench and at any time during the warranty period. Deflections greater than five (5%) percent of the inside pipe diameter sha l be considered failure of the bedding procedure and the Contractor may be required to re -excavate the trench and provide additional compaction along the side of the sewer pipe with no additional compensation for such work. 24,000.3.E4. Correcting Fa,,lty Grade: Any part of the trench excavated below grade shall be correctel with approved material thoroughly compacted without additional compensation to the Contractor. 24,000.3.E5. Pipe _Foundation in Poor Soil: When the bottom of the trench is soft or where in the opinion of the Fnkineer unsatisfactory i+-undation coudi- 24,000-7 2 /84 /4554h copyright 1984 Boneetroo, Rosene, Anderlik b Associates, Inc.