The backfill material shall be deposited in layers not exceeding 18 inches in thickness prior to compacting. Each layer shall be compacted with suitable mechanical tamping equipment. It shall be compacted sufficiently to obtain a field density which is at least 90% of theoretical density as determined by AASHTO method T-99. Field density shall be determined by AASHTO method T-147. In no event shall water jetting be allowed for compaction of backfill material.
(Ord. 20(1981) § 1; Ord. 8(1991) § 9)