Empirical calibration of hysteretic parameters for modelling the seismic response of reinforced concrete columns with plain bars

In this study, the hysteretic response of ductile Reinforced Concrete (RC) columns with plain bars is analyzed by evaluating the degradation of unloading and reloading stiffness with imposed inelastic displacement and the ?pinching? behaviour, based on experimental data. The dependence of the hysteretic parameters on selected potential predictors is investigated. Finally, the parameters describing the cyclic response of RC columns with plain bars are calibrated. The proposed cyclic macro-model is applied at the element level to check the consistency of its results with experimental outcomes. In addition, the prediction of the proposed model is compared with that of other response models proposed in the literature for modelling the seismic response of RC columns with deformed bars. It is observed ? also at structural level ? that the application of a model specifically dedicated to columns with deformed bars for predicting the cyclic response of columns with plain bars may yield to a significant overestimation of the cyclic degradation of the response and, in tune, to a significant underestimation of the displacement capacity.