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2 . 1 Haunching of the pipe shall be by hand placement and compaction of <br /> material in maximum 4 inch layers from the bottom of the trench to the <br /> springline of the pipe, taking care to fill all voids below and around the <br /> pipe. Backfilling shall be carefully continued in layers not exceeding 6 <br /> inches in thickness for the full trench width until the compacted fill is 12 <br /> inches above the top of the pipe. <br /> 2.2 During initial backfilling the fill shall be deposited evenly along both sides <br /> of the pipe from a height not to exceed 2 feet above the top of pipe, and <br /> fill shall not be dropped directly on the unprotected pipe surface. <br /> 2 .3 Where thrust blocks, encasement, or other cast-in-place concrete items are <br /> below grade, no backfilling shall start until the specific items have <br /> been inspected and approved by the Engineer or his authorized <br /> representative. <br /> 2.4 The backfill to one foot above the top of the utility shall be thoroughly <br /> compacted with curved end tamping bars under and on each side of the pipe <br /> and flat tamped between the pipe and trench wall and shall be completed <br /> before the remainder of the trench is backfilled. Initial backfill shall be <br /> compacted to 100 percent of maximum density as determined by AASHTO <br /> T- 180. No subsequent backfill will be permitted until the initial backfill <br /> has been accepted by the Engineer or his authorized representative . <br /> B . Subsequent Backfill <br /> i <br /> 1 . Subsequent backfill is that backfill between the initial backfill and the finished +r <br /> ground level or bottom of subbase. <br /> 2. Subsequent backfill material shall be placed full trench width in horizontal layers <br /> not exceeding 12 inches loose depth and compacted by power-operated tampers, <br /> rollers, or vibratory equipment to a density equal to 98 percent of the maximum <br /> density as determined by AASHTO T- 180 for pipe placed under and adjacent to <br /> roadways or paved surfaces, and 95 percent under areas where no pavement is to <br /> be constructed and vehicular traffic is not to pass over the pipe. Each layer shall <br /> be compacted to the specified density prior to placing subsequent layers. The <br /> thickness of the loose layer may be increased when in-place density tests show <br /> that the specified density can be obtained. ed <br /> C. Backfill Material <br /> 1 . Type 2 material shall be used for initial backfill and subsequent backfill with the <br /> following conditions : Initial backfill shall be predominately sandy material free <br /> from rock or stone greater than 1 1 /2 inches diameter, and the maximum allowable <br /> dimension of a stone or rock fragment for subsequent backfill shall be 6 inches. <br /> If in the opinion of the Engineer the Type 2 material will not provide adequate and <br /> uniform support for load distribution to the pipe, the Contractor shall obtain and <br /> place either Type 1 or Type 3 backfill as determined by the Engineer. <br /> 1i1 <br /> 2 . All excavated material not suitable for backfill shall be placed on site at an <br /> acceptable location, by Owner, or hauled off the job at the price set forth in the <br /> 02530 — Gravity Sanitary Sewer Piping <br /> 02530& 6 <br /> Ali <br /> SII <br />