Critique on Design of Pipeline Crossings

Pipeline crossings of natural barriers such as streams can involve many engineering problems. There are several hazards involved in buried stream crossings, especially those that have a moving stream bed material. There are potential and real dangers involved when excavations are made in a riverbed downstream from a buried pipeline crossing or any type of highway bridge structure. Pipeline bridge structures can be classified as cable suspension, combination pipeline-highway, deck bridge, and pipe trestle. The design of pipelines attached to highway bridges must give due consideration to live-load deflections. Pile trestles in general can be built at a very reasonable cost. In locations where pile trestle type of structures cannot be utilized, the use of a cable suspension span or a highway type of bridge structure can be built. However, these types of structures represent higher construction costs. Preliminary engineering studies must be included as part of the selection process before determining the type of crossing to be built.