Seismic Verification of the High Pressure Natural Gas Pipeline Komotini–Alexandroupoulis–Kipi in Areas of Active Fault Crossings

Abstract

A study for the evaluation of the effects of activation of faults induced by seismic activity on the High Pressure Natural Gas Pipeline Komotini–Alexandroupolis–Kipi, in Northeastern Greece, is presented. The associated basic assumptions, computational tools, numerical analysis options, pertinent code provisions and required checks are briefly outlined herein. The pipeline is modeled with either beam or shell elements, and the soil with appropriate nonlinear springs in all directions, accounting for soil–pipeline interaction. Geometric and material nonlinear analyses are carried out, accounting for large displacements, as well as adopting an appropriate nonlinear material law for the pipeline steel and an elastic–perfectly plastic law for the soil springs. The suitability of beam elements with respect to shell elements is addressed, from the points of view of accuracy, and computational cost. The selection of an appropriate pipeline length to be included in the model is investigated. Alternative countermeasures for critical sites, where the anticipated displacements cause strains exceeding the allowable limits, are proposed.