Experimental Investigation on Corrosion-Induced Failure Mode Transition and Seismic Behavior Deterioration of Reinforced Concrete Columns

This paper presents an experimental study carried out on six uncorroded and corroded reinforced concrete (RC) columns to investigate the seismic behavior and failure mode transition under cyclic loading. To do so, the impressed current method was adopted to accelerate the corrosion of stirrups and longitudinal reinforcements with separately different corrosion degrees. The seismic performance of each column was evaluated in terms of failure mode, hysteretic behavior, skeleton curve, stiffness degradation, energy dissipation capacity, and deformation proportion. Test results revealed that the flexural failure-designed column may fail in flexure-shear or shear as the corrosion degrees of stirrup increases. The load-bearing capacity, deformation, and energy dissipation capacity simultaneously underwent degradation. However, with the corrosion degree increased in the longitudinal reinforcement, the failure mode may be transitioned from shear failure to shear-dominated flexure-shear failure and eventually to flexure-dominated flexure-shear failure. Further, five commonly used shear strength prediction models were applied considering corrosion effects. The shear strength of corroded RC columns estimated by the average corrosion degree of the two mainly loaded limbs in stirrups shows better agreement with the test results in this study.