Influence of properties of large pipes on the reliability of pipelines

Abstract

Several factors affect the behaviour of pipelines constructed by butt welding of big diameter tubes. The heterogeneous properties of the tubes' metal and weld de-fect affect the working capacity of pipelines once put into service. The recourse to a reliability approach, during the projection of pipelines makes it possible, on the one hand to measure the risk incurred, by the association of a pipe-line fracture probability to a safety factor and on the other hand this allows to avoid its over sizing or to estimate the under sizing risk. Thus, in this context, the formulation put forward in the present work allows to reason qualitatively as well as quantitatively on the effects of various properties of pipes assembled end to end on the reliability of pipe-lines. An application example is given for big diameter pipes made from grade X52 steel.