Behavior of Cold Bend Pipes under Bending Loads

Abstract

Ground movement along a buried pipeline often places the line in net compression. The local buckling resistance at cold bends is less than at straight sections, and hence, local buckling tends to occur at bends. Correspondingly, this full-scale testing program was conducted to investigate the local and global load-deformation relationships for seven cold bend pipes under applied loads. The specimens were loaded under bending, axial load, and internal pressure until local buckling occurred, and their curvatures were subsequently increased to establish their postbuckling behaviors. It was demonstrated though these tests that the buckling strain of the cold bend pipes was considerably lower than a straight pipe and that the presence of internal pressure exhibited a predominant role on the specimens load-deformation behaviors. It was also established that the behavior of the specimens was relatively unaffected by the bending methods that were employed during cold bending.