The method of making the necessary backfill where excavation has been made shall be performed as follows: if it is a sewer that is to be covered, stone sand shall be tamped solidly under and around the sewer, with proper tools for that purpose, to a depth of twelve inches. The remainder of the backfill shall be deposited in layers not exceeding four inches in thickness, each of which shall be well pounded and rammed with a rammer of suitable weight, or an approved pneumatic tamper.
In case of excavations other than sewers, the earth backfill shall be compacted in four-inch layers the same as stone backfill, to a density of not less than ninety percent of the maximum density, as per specifications contained in the State of Ohio Department of Highways Construction and Material Specifications, the January, 1973, edition, containing the proper amount of moisture to obtain the maximum compaction.
At a point beginning not less than ten inches in depth below the surface level of any street or alley, any opening or excavation shall be widened by not less than eighteen inches on each side thereof and not less than eight inches of concrete shall be poured therein. Such concrete shall be covered by not less than two inches of material of the same kind and quality as the surrounding surface, which shall be compacted to the level of the surrounding surface.