(A) Concrete for manhole and lift station bases shall contain not less than 6 sacks of cement per cubic yard and shall have a water content, including free moisture in the aggregate, not exceeding 6 gallons per sack of cement. All concrete shall have a minimum 28-day strength of 3,000 psi when the test cylinder is cured under conditions similar to those surrounding the placed concrete. No concrete shall be placed which has a slump exceeding 2 inches when tested in accordance with provisions of the latest revision of A.A.S.H.O. Designation T-119. No concrete shall be placed in water.
(B) Manhole steps shall be placed at 16 inch intervals from the base of the manhole. The sewer lines may be discontinuous through the manholes or the pipe may be laid through and broken out after the base has been formed.
(C) The concrete base shall be finished with smooth, uniform, full-section channels to control the flow of sewage. A smooth, uniform radius shall be provided in manholes where the direction of flow changes.
(D) The outside of masonry or brick manholes shall be plastered with portland cement mortar at least ½ inch in thickness. The outside of precast manholes shall be plastered if necessary to prevent seepage of ground water through the manhole walls.
(E) All P.V.C. sewer pipe connections to manholes shall be made with a transite collar with rubber gaskets to provide a watertight seal or with a suitable caulked joint.
(F) The top of each manhole shall be accurately set so that it will be flush with paved or concrete surfaces, 3 inches below the surface of graveled or unimproved roadways, and 6 inches above the surface in open areas.
(G) During the manhole construction, the contractor shall keep all pavement, concrete, tile, and other debris from entering the sewer pipe or accumulating on the manhole base.
(H) Backfill around each manhole shall conform to the compaction requirements for the adjacent trench.
(1981 Code, § 28-145) (Ord. 649, passed 8-8-1978)