Lumped spring model parameters of RC frame elements for seismic performance assessment

Abstract This study presents lumped spring model parameters for nonlinear seismic analysis of reinforced concrete (RC) frame structures. The modified Ibarra‐Medina‐Krawinkler (M‐IMK) hysteresis model is used as a lumped spring to simulate the inelastic behaviour of a RC frame element. The influence of loading protocols on the calibration of model parameters is investigated and compared with other hysteresis models, such as the original IMK and Bouc‐Wen‐Baber‐Noori (BWBN) models. Less dependent on the loading protocol used for model identification, the parameters of the modified IMK hysteresis model are calibrated to model a database of 383 rectangular RC columns. To simplify the calibration process, the model parameters that define the monotonic response are determined based on code and empirical equations, while the parameters that control the hysteretic degradations are calibrated against the experimental results. The calibrated model parameters are used to develop regression equations for the model parameters based on physical variables, such as loading, dimensions, and material properties. It is found that the model parameters obtained from the experimental calibration and regression equations generate similar hysteresis curves. The performance of the lumped spring model to nonlinear time history analysis of RC structures subjected to earthquakes is also evaluated through a series of pseudo‐dynamic hybrid simulations.