Collapse Performance of HTS (Helical Seam Two Step) Welded Line Pipe

Line pipe intended for offshore applications has to be designed predominantly with regard to external pressure in order to avoid collapse. High resistance to external pressure is vitally important for the use of pipes in such applications. A test program has been carried out in order to verify the resistance of HTS (helical seam two step) welded line pipe against collapse. It was demonstrated that the two step pipe manufacturing process has a beneficial effect on collapse resistance. HTS pipes therefore shows a good collapse performance compared to the design equations given in relevant offshore standards. One aim of the work carried out was to quantify the influence of relevant parameters on the result of full-scale collapse test by finite element analysis. The actual collapse pressures and those predicted using currently available design equations are compared and verified for various boundary conditions. The paper concludes with a discussion of the major findings and with a brief outlook to future research issues.Copyright © 2006 by ASME