(A) Areas not subject to vehicular traffic.
(1) For the purposes of this subchapter, trenches shall be considered subject to vehicular traffic if any portion of the excavation is located within four feet of a roadway or alley.
(2) The trench above the pipe embedment to the ground surface shall be backfilled with Class I, II, III or IV materials. The contractor shall consolidate the backfill by the back-and-forth travel of a suitable roller, wheeled device or other similar heavy equipment until no further settlement is obtained.
(3) Heavy equipment shall not be used until there is a cover of not less than three feet over the pipe. To assist in promoting maximum settlement, the surface of the trench shall be left in a slightly-rounded condition. Periodic dressing of the backfill in the trench to promote drainage and safety conditions shall be made during the course of the contract as required or ordered by the engineer.
(B) Areas subject to vehicular traffic.
(1) The trench above the pipe embedment to the surface, where located in areas subject to vehicular traffic, shall be backfilled with granular backfill materials deposited in lifts of maximum height, or 12 inches, to satisfy the compaction requirements. Each layer shall be thoroughly compacted by mechanical tamping to not less than 95% density as determined by the Standard Proctor test (ASTM D698).
(2) Granular backfill materials shall terminate at a point below finished grade sufficient to allow for the placement of permanent surface materials. Where the permanent surface is asphalt or concrete, the aggregate base thickness shall be the specified thickness of the pavement material plus six inches.
(3) For portions of the trench surface not subject to traffic, the backfill material shall end six inches below the finished grade. This six-inch depth shall be filled with good top soil and seeded in accordance with this subchapter.
(C) Backfill prohibitions and requirements.
(1) No fill shall be placed against any manhole or other structure until placed concrete has been allowed to cure for at least three days.
(2) Backfill shall be placed in such a manner that the structure will not be damaged by shock from falling earth. The backfill material shall be deposited and compacted as specified for final backfill, and shall be placed in such a manner so as to prevent eccentric loading and excessive stress on the structure.
(Ord. 2010-3, passed 10-6-2010)