Modeling Nonlinear Cyclic Load-Deformation Response of Corrosion-Damaged Reinforced Concrete Columns

Abstract

This study presents a lumped plasticity modeling method for simulating the nonlinear load-deformation response of corroded reinforced concrete (RC) columns with rectangular and circular cross-sections. The proposed modeling method utilizes an extended column database to enhance the robustness of the database and considers cyclic degradation. An extensive database of 138 rectangular and 25 circular corroded RC column specimens was constructed to calibrate the model parameters. Subsequently, semi-empirical predictive equations were developed using multiple linear regression analysis for estimating the model parameters, including the corrosion level and column design parameters. The proposed predictive equations were validated against experimental data and showed better accuracy than those of the existing models in terms of strength and initial stiffness. The seismic collapse capacity of the bridge and seismic demand of bridge columns were investigated as an application of the proposed modeling method to an RC bridge system with various corrosion levels. Incremental dynamic analysis results revealed about 46% reduction in the collapse capacity for the bridge with columns that have a 30% corrosion level compared to that with uncorroded columns. Owing to the monotonic and cyclic strength degradation, the proposed lumped plasticity model achieved higher seismic drift demands of columns compared to that obtained using the distributed plasticity model. Further, the seismic drift demands of columns modeled by the proposed method showed a 1.13-1.26 times stronger relationship with corrosion compared to that of the distributed plasticity model.