Pipe Collapse Under Combined Pressure, Bending, and Tension Loads

Abstract

The paper presents results of a combined experimental and analytical study of the response and stability of pipelines under combined bending, pressure and tension loads. Such loads are encountered during the installation of offshore pipelines. Test facilities for three load combinations consisting of bending and pressure, tension and pressure, and tension and bending are described. Experimental results obtained from relatively thick-walled model tubes, where the diameter-to-thickness ratio is between 10 and 40, are presented. These include the response of the tubes to the combined loads and the loads at collapse. For the first two load combinations, collapse envelopes for various loading histories are presented. Preliminary results from an ongoing study of the pipe response under combined tension and bending are also presented. Numerical solution procedures for these combined loads have been developed. They are verified by comparing the predictions to the experimental results.