Effect of External Pressure on Strength of Short Tubular Members

Tubular members in offshore installations are often subjected to the simultaneous action of axial forces, bending moments, and hydrostatic pressure. Thus, the interactions of forces, moments, and external pressure must be considered in the design of these members. In this study, sectional capacities of tubular members under the action of combined loads are determined by using various failure criteria, and the results are then compared with those obtained from a recent test for short tubular steel columns. In examining the influence of hydrostatic pressure, cap‐end forces are not included explicitly. For most short tubular steel members of dimensions typically used in offshore construction, the failure mechanism may be characterized by the yielding of the material, followed by a buckling in the plastic or strain‐hardening region. Strengths of these members may be predicted by simple equations that are derived from either von Mises or Tresca yield criteria. However, when the members are subjected to relatively high hydrostatic pressure, elastic or inelastic buckling, caused by the presence of residual stresses, may occur before the yield stress is reached.