ON THE NUMERICAL SIMULATION OF THE RESPONSE OF GAS PIPELINES UNDER COMPRESSION

Steel gas pipelines may be subjected to buckling failure under large compressive straining, caused by seismically induced ground deformations. This paper further elaborates on the buckling response of this type of networks, through the presentation of representative results from a series of axial compression static analyses that were conducted on segments of steel gas pipelines. Above ground and embedded segments of diverse radius to thickness ratios (R/t) were simulated by means of inelastic shell elements. The trench of embedded pipelines was modelled using solid elastic elements, while an advanced contact model was used to simulate the pipe-soil interface. Salient parameters that affect the axial response, including the internal pressure and the existence of imperfections on the segment, were considered in this study. In line with previous evidence, the results reveal a reduction of the axial response of the pipe segment with increasing levels of internal pressure. In parallel, internal pressure leads the limit stresses to occur at progressively higher axial deformations, while limit loads computed for embedded pipelines are higher compared to those predicted for equivalent above ground pipelines, as a result of the soil confinement.