Full-scale pipeline buckling test in hyperbaric chamber

Pipelines are important in transporting oil and gas in offshore engineering. During the service condition, this external water pressure could be compensated by the internal pressure induced by the gas or oil within the pipeline. However, during the pipe-laying or maintenance, the internal pressure in the pipeline will disappear. The huge external water pressure will cause local buckling or crushing first at defect or damage part of pipelines. Experimental research is one of the important means to investigate the pipeline buckling phenomena. Most of the existing hyperbaric chambers are in small scale, which could not perform experiments with the actual pipe used in the offshore engineering. Due to this reason, the most of the published experimental results obtained from these hyperbaric chambers are in small scale where the cross section size was reduced with same diameter-thickness ratio. In order to avoid the scale effects on the experimental phenomena and results, a full-scale hyperbaric device was designed by the Institute of Offshore and Naval Engineering of Tianjin University, China. Twelve series of full-scale buckling tests were conducted in this paper, with the intention of investigating the influence of diameter-thickness ratio and initial imperfection on the buckling pressure. Furthermore, the numerical simulation using ABAQUS was performed to compare the experimental results. The comparison shows a good agreement, where the average difference is about 6% to 7%.