ASYMMETRIC RESTORING FORCE MODEL AND PARAMETER IDENTIFICATION OF REINFORCED CONCRETE COLUMN

Subjected to severe excitations generated by strong ground motions, a reinforced concrete (RC) column usually exhibits the behavior of strength degradation, stiffness deterioration, pinching effect, and asymmetric hysteresis. However, the traditional restoring force models cannot rationally describe the above hysteretic behavior. An improved asymmetric Bouc-Wen-Baber-Noori (BWBN) model was developed, taking into account the strength degradation, stiffness deterioration, pinching effect and asymmetric hysteretic behavior, by introducing an asymmetric shape parameter into the differential function between hysteretic displacements and relative lateral displacements. Meanwhile, an efficient method was proposed to identify the parameters of the asymmetric BWBN model, based on the differential evolution (DE) algorithm. The efficiency and accuracy of the proposed model were validated by comparing with the experimental data of pseudo-static loading test of RC columns.