Seismic Performance of Flexural Reinforced Concrete Columns with Corroded Reinforcement

This paper presents an experimental study carried out on eight full-scale uncorroded and corroded reinforced concrete columns that were subjected to simulated seismic loading to investigate the effects of reinforcement corrosion on the seismic behavior of columns that failed in flexure. The main variables are the corrosion levels of reinforcement and applied axial force ratios. The seismic performance of test specimens was assessed in terms of crack pattern, hysteretic response, yield displacement, lateral load resistance, drift capacity, displacement ductility, and energy dissipation capacity. The results highlighted that the corroded columns suffered a significant degradation of strength and lateral drift capacity as compared to uncorroded columns. In addition, it is noteworthy to observe that the failure mode of corroded columns switched from flexural failure to flexural-shear failure and sudden axial failure when they are highly corroded and subjected to high axial force. An empirical equation based on the maximum pit depth of corroded longitudinal reinforcing bars was proposed to predict the residual flexural strength of corroded columns. Furthermore, based on the shear strength model proposed in ASCE/SEI 41-13, methods were proposed to estimate the shear strength of corroded columns failed in flexural-shear failure and axial failure, which consider the contribution reductions to shear strength of transverse reinforcement and concrete due to corrosion. Among these methods, the shear strength of corroded columns estimated based on the corrosion mass loss and average residual cross-sectional area was not conservative as compared to the test results. In contrast, the shear strength of corroded columns predicted using the minimum residual cross-sectional area of transverse reinforcing bars showed good and reliable correlation with the experimental results.