Impact of corrosion on the lateral load response of RC multi-column bents with flexure-shear critical members

Reinforced concrete (RC) multi-column bents in bridge overpasses exposed to aggressive environments are highly susceptible to corrosion-induced deterioration, which can significantly compromise their lateral load-carrying capacity and seismic performance. This study investigates the influence of corrosion on the nonlinear lateral behavior of RC bridge bents through a comprehensive set of static pushover analyses. A parametric study is performed assess the lateral behavior of typical bridge bent configurations considering variable corrosion levels affecting reinforcement properties and confinement efficiency. The modeling approach captures the degradation of flexural capacity, stiffness, and ductility. Two simulation strategies are examined: one exhibiting only flexural failure, and another characterized by coupled flexure-shear mechanisms. This dual comparison allows assessment of how corrosion impacts the balance between flexural and shear capacities and the possible transition from flexure-shear to flexure-dominated behavior as corrosion progresses. Pushover analyses are carried out for multiple corrosion scenarios, enabling a quantitative assessment of lateral strength degradation, displacement capacity, and ductility reduction. The results highlight the nonlinear progression of damage as corrosion intensifies and emphasize the need to incorporate realistic degradation models in seismic vulnerability assessment of bridge systems. This study provides valuable insights for the evaluation and prioritization of retrofitting strategies for RC overpass bents in aggressive environments.