Numerical Study for Asymmetric Deterioration of Reinforced-Concrete Marine Piles Under Localized Corrosion Subjected to Multi-Directional Lateral Loading

Chloride-induced corrosion reduces the tensile capacity of the reinforcement and the effective area of the concrete cross-section of reinforced concrete (RC) piles. This study presents a two-stage framework that reproduces localized multi-rebar corrosion and the subsequent lateral cyclic response in a single explicit analysis, so that corrosion damage is inherited by the loading stage rather than re-imposed: Stage I applies the corrosion expansion to solid rebar elements through a thermal analogy, and Stage II imposes cyclic lateral loading, capturing the coupled evolution of concrete damage and pile-soil interaction. The framework is validated against experiments on RC piles with one to three corroded rebars, reproducing the hysteresis loops, skeleton curves, and stiffness degradation, with the peak load of the uncorroded specimen within 6%. For a full-scale pile with six eccentrically corroded rebars subjected to multi-directional loading, the critical direction is the one that places the corroded reinforcement in tension, which can be identified from a corrosion survey alone. Therefore, assessing the bearing capacity of corroded marine piles should consider the unfavorable loading direction since adopting a single direction would overestimate the capacity by up to a factor of 1.8.