Encasement of underground utility crossings where required is intended to serve one or more of the following purposes:
(A) To allow replacement of utility without future disruption of roadway structure.
(B) To vent or drain leaks of volatile gases or liquids that might occur under the roadway structure.
(C) To serve as bridge or carrier through unstable soil structure.
(D) To prevent cavitation under pavement structure from leaks of pressurized liquids.
(E) To allow ease of insertion and coating protection of utility conductor or carrier.
(F) To provide protection of utility conductor or carrier from superimposed loads and/or “dig-in” damage.
(G) Casing pipe shall be designed to withstand the load of the highway and any other superimposed loads. The casing shall be continuous either by one-piece fabrication or by welding or jointed installation approved by the Department Under-ground utility crossings without encasement, when permitted, will generally preclude future maintenance or repair within the area between the ditch lines or toes of slopes.