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necessary to obtain a suitable foundation. The Engineer will notify the <br /> Contractor, in writing, of the necessity for and extent of the material to be <br /> ' removed and the Contractor shall remove such unsuitable material as <br /> soon as possible and backfill in accordance with the requirements for Class <br /> B Bedding . All unsuitable material shall be disposed of by the Contractor. <br /> ' 8 . PIPE TRENCH BACKFILL <br /> ' A. INITIAL BACKFILL <br /> 1 . Initial backfill shall be placed as soon as possible after laying the pipe and <br /> rshall maintain a pace with the pipe laying so that no more ' than five pipe <br /> joints separate laying and backfilling operations . Initial back fill shall <br /> include all haunching and backfill from the top of the bedding to a <br /> compacted depth of twelve inches over the pipe . All haunching and <br /> backfilling shall be done in the dry . <br /> 2 . Initial backfill shall be done as specified below: <br /> a. Haunching of the pipe shall be by hand placement and <br /> compaction of material in maximum 4 inch layers from the bottom <br /> of the trench to the springline of the pipe , taking care to fill all <br /> voids below and around the pipe . Backfilling shall be carefully <br /> continued in layers not exceeding 6 inches in thickness for the full <br /> trench width until the compacted fill is 12 inches above the top of the <br /> pipe . <br /> b . During initial backfilling the fill shall be deposited evenly along both <br /> ' sides of the pipe from a height not to exceed 2 feet above the top of <br /> pipe, and fill shall not be dropped directly on the unprotected pipe <br /> surface . <br /> c . Where thrust blocks , encasement, or other cast-in-place <br /> concrete items are below grade, no backfilling shall start until <br /> ' the specific items have been inspected and approved by the <br /> Engineer or his authorized representative . <br /> ' d . The backfill to one foot above the top of the utility shall be <br /> thoroughly compacted with curved end tamping bars under and <br /> on each side of the pipe and flat tamped between the pipe and trench <br /> wall and shall be completed before the remainder of the trench is <br /> backfilled . Initial backfill shall be compacted to 100 percent of <br /> maximum density as determined by AASHTO T480 . No subsequent <br /> ' backfill will be permitted until the initial backfill has been <br /> accepted by the Engineer or his authorized representative . <br /> B . SUBSEQUENT BACKFILL <br /> 1 . Subsequent backfill is that backfill between the initial backfill and the <br /> C : \ Down1oad \ techspec - 02403 . doc 02403 - 5 <br />