Axial compression stability of corroded circular steel tubes in simulated seawater environments

Abstract

To investigate the influence of seawater corrosion damage on the axial compression stability of circular steel tubes, this study proposes a novel method (hereinafter referred to as the ‘thickness equivalent method’) for calculating the equivalent wall thickness based on the yield load determined through material property tests. To this end, a formula for calculating the equivalent regularised slenderness ratio of corroded circular steel tubes is derived. Subsequently, corrosion, material property and axial compression tests are conducted using circular steel tubes with different sectional dimensions, and numerical models are developed. The numerically obtained load–lateral displacement and load–strain curves are in good agreement with the test curves, validating the accuracy of the numerical models. Finally, a parameter study is conducted using the validated numerical models. To facilitate the examination of corroded circular steel tubes, a novel formula, representing a continuous function of the regularised slenderness ratio as opposed to the previous piecewise function, for computing the stability coefficient is derived. The test results demonstrate that the proposed method accurately predicts the ultimate axial compression bearing capacity of corroded circular steel tubes. Furthermore, based on the theoretical derivation, the relationship between the axial compression ultimate bearing capacity and the corrosion ratio for ϕ48 × 3 and ϕ57 × 3.5 steel tubes, considering various equivalent regularised slenderness ratios, is established.