Performance of semi-actively controlled building frame using mr damper for near-field earthquakes

Abstract

Most of the studies on the control of building frame using MR damper are investigated for far-field earthquake records, and a considerable reduction in responses is shown. However, MR dampers have some significant drawbacks like the saturation of MR dampers and its performance variability with respect to the ground motions. It has been found that when the predominant frequency of the earthquake is much away from the natural frequency of the structure, the response reduction becomes significantly less. The reason for this may be attributed to the less values of relative displacement and velocities of the floors which primarily influence the force generated in the damper for a given voltage. The characteristics of the near-field ground motion are distinctly different from the far-field ground motion. The performance of the MR damper for the near-field earthquake is not well investigated. In the present study, the performance of the MR dampers is studied for two types of near-field earthquakes, namely Bam (directivity effect) and Chichi (fling step effect) earthquakes. A limited number of MR dampers are employed for response reduction.