Instability of Pipelines on Slopes

Abstract

A serious incident occurred during construction of a 36-inch pipeline in Colombia. A 500 m length of pipe on a hillside slipped on its supports, buckled, and slid down the hill, causing deaths and serious material damage. On a steep slope friction is not large enough to carry the downslope component of the weight. The frictional force from the supports then acts upslope. If the temperature subsequently increases, the frictional force partially reverses. The longitudinal force becomes more compressive and the pipeline can lift off the supports in overbends. A graphical construction gives a simple method of assessing the stability of the pipe in an arbitrary profile. The incident has important lessons for the construction of pipelines in steep terrain.