Structural analysis of pipelines is a well-established topic in engineering practice. Different professional societies or national and international authorities have provided Design Codes with procedures that, in spite of being well accepted, contain assumptions whose implications are not always well understood.

In this paper, we present a comparison between a simplified well-established method to compute the safety of gas pipes when crossing faults, and a more refined approach: the Finite Element Method (FEM) that enables us to consider large displacements and nonlinear material properties and shows some discrepancies relative to the classical approach.