Large-Diameter Pipe Subjected to Landslide Loads

When a pipeline crosses a landslide, it is subjected to combined loads, which can result in bending and subsequent ovalization of the pipe cross section. When compressive stresses cause buckling and ovalization, then the tensile stresses rarely result in these types of failures. Reliable mitigation measures could be carried out quickly at modest cost by performing a pipe stress-strain state assessment that takes into consideration elastic-plastic deformations. Therefore, this paper studied the response of the thin-walled cylindrical pipe subjected to combined beam load factors and internal pressure using a new engineering approach. This approach relied on a technique that reduces the problem to one dimension, and uses the plasticity and membrane theory of shells. A stress-strain diagram of pipeline material was obtained from the tensile test and was approximated with two linear dependences in the elastic and plastic zones. The actions of internal pressure, bending moment, and longitudinal force on the straight pipe element and distribution of stresses and strains in the pipe cross section were analyzed. The results of this paper show how variations of external loads affect pipe flexural rigidity and were compared with experimental outcomes. (C) 2012 American Society of Civil Engineers.