Collapse of UOE manufactured steel pipes

The manufacturing method (seamless, UO, UOE) has a considerable influence on the collapse pressure of steel pipes. For UOE manufactured pipe, a significant reduction in collapse strength has been observed compared to not expanded pipe. A research program has been carried out to investigate the effect of the manufacturing process on the collapse and local buckling behaviour, The results of collapse tests on three 20-inch UOE manufactured pipes and one seamless pipe are presented. The D/t ratios were 45, 27, 22 and 29. The paper also contains the results of finite element calculations, carried out to obtain more information on the parameters governing the collapse resistance of UOE manufactured pipes, The influence of the Bauschinger effect on the collapse resistance was determined. The results of probabilistic calculations with relevant experimental data related to collapse of pipes have been collected in a database and compared with the available design formulae. Design formulations for collapse with appropriate safety factors, calibrated against experimental and numerical models using probabilistic methods, have been selected for the practical range of design situations.