Simulated seismic behavior of welded steel tee joints and elbows used in natural gas networks

Abstract

Welded elbows and tee joints are key components within the natural gas network, hence understanding their seismic behavior is critical to ensure the robust seismic performance of the piping network. This paper summarizes results from an experimental and numerical effort aimed at understanding the cyclic behavior of welded steel tee joints and elbows internally pressurized with air. Specifically, four tee joint and four elbow specimens were tested with a pseudo-static increasing-amplitude cyclic displacement-controlled protocol. Seven specimens exhibited a ductile failure while one specimen observed a brittle failure. High fidelity finite element models of each specimen were developed within Abaqus and their material properties were optimized to obtain robust comparison with the experimental results. Notably, the high fidelity finite element models were able to predict the moment-rotation behavior and the deformed shape of the specimens with significant accuracy for the seven fittings exhibiting a ductile failure.