PERFORMANCE-BASED DESIGN OF BURIED STEEL PIPES AT FAULT CROSSINGS

Abstract

Buried steel pipes are commonly used in oil and gas industry for transmitting hydrocarbon products. Fault crossing is considered as one of the most important extreme events. Buried steel pipes are more vulnerable to compressive strains as compared to tensile strains. Therefore, the orientation angle of the pipe with respect to the fault should be arranged in such a way so as to promote net tension in the pipe. In this study, a numerical study is carried out on a simplified numerical model to determine the seismic demand on steel pipes at fault crossings. The proposed model permits plastic hinge formation in the pipe due to incrementally applied fault movements, allow determining the critical length of the pipeline and measure strains developed on the tension and compression sides in the pipe. Based on the analyses carried out on the simple model and previous studies, two performance levels are defined for pipelines; namely, fully functional and partially functional.