Karvelis, A. C., Melissianos, V. E., and Gantes, C. J. (2017). Numerical Investigation of Local Buckling of Steel Pipelines under Seismic Fault Rupture. Proceedings of the 9th Hellenic National Conference on Steel Structures, Larisa, Greece (in greek)
Summary | Onshore buried pipelines are the main mean for fuel transportation in order to meet the increasing energy demands of the economy and extend over long distance. When seismic areas are attempted, eventual pipe – fault crossing is increased. A fault activation leads to imposed large permanent ground displacements on the pipe, which the latter has to follow. The main failure modes in this case are tensile fracture of the girth welds between the adjacent pipe parts and local buckling of the pipe wall. Pertinent safety checks are carried out in terms of tensile and compressive strains, respectively. The occurrence of local buckling is numerically investigated in the present study and the pertinent code-based strain limits are evaluated. Firstly, a numerical model is formulated that is calibrated based on experimental results from four-point bending tests. Then, a simplified numerical model is developed in order on the one hand to investigate the main parameters affecting the local buckling occurrence and on the other hand to formulate the basis for the next step of the research, where the surrounding soil will be taken into account. The evaluation of the numerical results reveals the unstable post-buckling behavior of the pipe. Moreover, the effect of the diameter over thickness ratio on the ultimate load and the critical buckling strain is investigated.