A utility pipe rests on a shaped stable trench foundation bedded in sand and gravel, requiring a minimum of eighteen inches of cover over the pipe. The bedding consists of two-inch minus material for hard wall pipe and three-quarter-inch minus material for PVC pipe, with an additional six inches minimum of sand or gravel required in unstable areas or through rock excavation. The trench features a minimum width of the pipe outer diameter plus eighteen inches, with side slopes conforming to local, state, and federal OSHA requirements. Compacted backfill fills the trench up to the subgrade, topped with a minimum of eight inches of road base and four inches of minimum asphalt pavement, or matching existing asphalt thickness plus one inch if greater. A saw cut is required to clean and tack coat the pavement edges.
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