2004-013.C - Laserfiche WebLink

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finished ground level or bottom of subbase . 2 . Subsequent backfill material shall be placed full trench width in horizontal layers not exceeding 12 inches loose depth and compacted by power-operated tampers , rollers, or vibratory equipment to a density equal to 98 percent of the maximum density as determined by AASHTO T- 180 for pipe placed under and adjacent to roadways or paved surfaces , and 95 percent under areas where no pavement is to be constructed and vehicular traffic is not to pass over the pipe . Each layer shall be compacted to the specified density prior to placing subsequent layers . The thickness of the loose layer may be increased when in-place density tests show that the specified density can be obtained. C . BACKFILL MATERIAL 1 . Type 2 material shall be used for initial backfill and subsequent backfill with the following conditions : Initial backfill shall be predominately sandy material free from rock or stone greater than 1 1 /2 inches diameter, and the maximum allowable dimension of a stone or rock fragment for subsequent backfill shall be 6 inches . If in the opinion of the Engineer the Type 2 material will not provide adequate and uniform support for load distribution to the pipe, the Contractor shall obtain and place either Type 1 or Type 3 backfill as determined by the Engineer. 2 . All excavated material not suitable for backfill shall be placed on site at an acceptable location, by Owner, or hauled off the job at the price set forth in the accepted Bid Documents . All material that is brought in from other sources for backfill shall be at the price set forth in the Contract. 3 . Excavated material to be used for backfill shall be neatly deposited at the sides of the trenches where space is available to protect against caving or sloughing into the trench. Where stockpiling of excavated material is required, the Contractor shall coordinate the site location with the Engineer and shall maintain his operations to provide for natural drainage and not present an unsightly appearance . No excavated material shall be placed on private property without the consent of the property owner. D . COMPACTION METHODS 1 . Mechanical compaction shall be accomplished using pneumatic or gasoline-powered tampers or flat-plate vibrators, with the exception that the first two feet of backfilling over the pipe shall be compacted by hand- operated tamping devices . 2 . Flooding or puddling with water to consolidate backfill is not acceptable, except where sand is encountered below unpaved areas only, and only with prior approval by the Engineer. The flooding or puddling operation shall be repeated with each two feet of backfill placed . C : \ Down1oad \ techspec - 02403 . d0c 02403 - 6