Hysteretic model parameters for seismic performance assessment of cyclically degraded reinforced concrete columns

This study proposes integrated hysteretic model parameters of a lumped plasticity model for the nonlinear load-deformation response of reinforced concrete columns regardless of their failure mode and cross-sectional shape. To do this, hysteretic model parameters were calibrated using an experimental database of 358 rectangular and 289 circular column specimens exhibiting flexure, flexure-shear, and shear failure. Model parameters for stiffness, strength, rotation capacity, and cyclic damage were estimated for each specimen. Semi-empirical equations for these parameters were developed through regression analyses using column design parameters. Comparison with two existing equations revealed that the proposed equations achieved better accuracy in predicting cyclic responses. The results demonstrated that the proposed model parameters provided the most accurate predictions for the cyclic response of the most of the specimens. The cyclic response and collapse capacity of columns modeled using the proposed method under various loadings were further examined and compared with those of existing modeling methods. The collapse capacity obtained from the proposed method falls within the range predicted from the two existing methods. Furthermore, the seismic response of columns determined by the proposed equations closely matches the response of columns subjected to a near-fault loading protocol.