Experimental investigation on the seismic performance of corroded reinforced concrete columns designed with low and high axial load ratios

This study experimentally examined the seismic performance of corroded reinforced concrete (RC) columns designed with low and high axial forces. To do this, ten RC columns were designed and fabricated as the test specimens. They were categorized into two groups corresponding to low and high axial load ratios (ALRs), i.e., 0.1 and 0.45, respectively. Each column group consisted of an uncorroded column and four corroded columns with growing corrosion rates of 2%, 5%, 10%, and 20%. The seismic performance of each of column specimens was tested under quasi-static cyclic loadings from failure modes, hysteresis and backbone curves, ductility, stiffness, and energy dissipation. The results show that the axial load level significantly affects the seismic performance of corroded RC columns. The severely corroded RC column designed with a high ALR fails in a brittle mode, showing the detrimental and coupling effect of reinforcement corrosion and axial loads. Finally, six shear strength models that were commonly used to predict the shear strength of uncorroded columns were applied for corroded columns with accounting for the deterioration of concrete and reinforcement materials. The prediction results show that the model proposed by FEMA 273 has the highest accuracy among the considered models in predicting the shear strength of corroded columns. This study reveals the effect of axil loads on the nonlinear behavior of corroded columns under cyclic loadings. The results can benefit the engineers' understanding of seismic performance of corroded columns.