3D Modeling of Galvanic Corrosion and Seismic Vulnerability in Chloride-Exposed Reinforced Concrete

Reinforced concrete (RC) buildings in coastal seismic regions are exposed to coupled deterioration processes driven by chloride-induced corrosion and earthquake loading. This interaction is particularly critical along the Mexican Pacific coast, where persistent marine exposure coincides with high seismic hazard. Nevertheless, current models lack a consistent multi-physics framework that integrates chloride transport, electrochemical heterogeneity (including galvanic interactions), and seismic structural response. This study quantifies the influence of corrosion on seismic collapse probability by explicitly modeling the coupled mechanisms of moisture transport, chloride ingress, and electrochemical potential distribution in RC members. A three-dimensional mechanistic framework is adopted to capture the spatial variability in corrosion, including galvanic interactions between passive and active reinforcement regions. A representative scenario is examined in which a corner column remains in continuous contact with seawater, promoting localized chloride accumulation and sustained corrosion activity. The resulting nonuniform section loss is incorporated into nonlinear structural models subjected to mainshock–aftershock sequences. The results show that corrosion-induced heterogeneity, amplified by galvanic coupling between passive and active zones, accelerates strength and stiffness degradation. Compared to conventional uniform corrosion assumptions, this effect leads to a significant increase in early collapse probability, with values increasing from near-zero levels to approximately 0.6–0.9 at moderate seismic intensity levels. These findings emphasize the need to account for coupled transport and electrochemical processes, as well as localized exposure conditions, in the seismic assessment of RC structures in aggressive coastal environments.