Effect of corrosion in reinforced concrete frame components on pushover behavior and ductility of frame

Chloride-induced corrosion of reinforced concrete (RC) is one of the main reasons for decreasing the seismic performance level of RC structures over their lifetime. In the present study, base shear capacity and ductility were considered as criteria for evaluating seismic performance of the RC frame. The impact of corrosion on the ductility and base shear capacity of a two-dimensional single-story single-span RC frame was investigated using nonlinear static analysis considering the deterioration of the mechanical properties of the rebar and concrete. The corrosion damage model was implemented using fiber sections and nonlinear elements, and then pushover analysis over 0, 15, 30, 45, and 60 years of life was performed. The strain penetration effect was considered in the fiber model at the column-footing joints. The accuracy of modeling was validated with experimental data of the RC frame subject to cycle loading. The final results showed that by decreasing the water-to-cement ratio and increasing the cover thickness, the seismic performance of the RC frame is preserved over a lifetime. The time-dependent ductility of the RC frame was evaluated at two structural and cross-sectional levels. The results revealed that the corroded RC frame has a lower base shear capacity, ultimate drift, and ductility than the intact RC frame. Also, the corrosion-induced deterioration of rebar and concrete significantly decreases the seismic performance of the corroded RC frame.