Experimental investigation of the seismic performance of corroded reinforced concrete coupling beams

Abstract

In this study, a seismic performance assessment of six reinforced concrete (RC) coupling beam specimens with accelerated corrosion is conducted by combining accelerated corrosion methods with quasistatic loading tests. A detailed comparison of the corrosion damage, failure modes, and mechanical performance differences of the coupling beam specimens under different corrosion levels is presented. The degradation patterns of the coupling beam seismic performance are revealed through analyses of the hysteresis behavior, stiffness degradation, energy dissipation capacity, and proportions of bending, shear, and slip deformations in relation to the corrosion level. The experimental results indicate that with increasing corrosion level, the load-carrying, deformation, and energy dissipation capacities of the coupling beams continuously decrease. The cracking pattern of corrosion-induced cracks is influenced by the reinforcement arrangement, with diagonal reinforcement causing cracks to propagate diagonally. The nonuniform distribution of corrosion leads to asymmetric loading in coupling beam specimens with higher corrosion ratios, significantly weakening the load-carrying and energy dissipation capacities and making the specimens more prone to sudden brittle shear failure without warning. Corrosion-induced damage degrades the shear capacity of the coupling beams, increasing the proportion of shear deformation.