Experiment and analysis of torsional seismic responses for asymmetric structures with semi-active control by MR dampers

摘要

This paper focuses on the mitigation of the coupled translation and torsion responses of an asymmetric structure by a magnetorheological (MR) damper. A double-sigmoid model of the MR damper is presented on the basis of the experimental results, and the validity of this proposed model for predicting the hysteretic behavior of the MR damper is favorably proved by comparing the simulation results with the experimental data. A multi-state control strategy (MSC) which uses the velocity response as the state-switch parameter is developed for the torsional seismic response control of the asymmetric structure. The parameters of this control strategy are optimized by a genetic algorithm (GA) method. Finally, a shaking table test is carried out to evaluate the effectiveness of MR dampers for the torsional seismic response control of a three-story reinforced concrete frame-shear wall eccentric structure. The results indicate that the MR damper is quite effective for the coupled translation and torsion response reduction. The proposed semi-active control strategy has advantages over the performance of passive systems for different ground motion inputs and various excitation levels. Moreover, the location of MR dampers has a significant effect on the response control.