Using a limited set of mr dampers for improving structural seismic response

Control is one of the methods used for reducing structural response to earthquakes. Optimal active control algorithms allow calculating the forces that should be applied by supplemental devices in order to yield desired structural behavior during an earthquake. However, active devices require large amounts of external power, which are not always available in the real time. Therefore, more economical semiactive devices, combining the best features of passive and active control systems, are used for protecting structures against earthquakes. This study is aimed at finding a simple and effective method for optimal control of structures using magnetorheological dampers. An algorithm for finding effective dampers' locations is used. Additionally, high-efficiency amplifiers are used for connecting the dampers while decreasing the number of damping units. The location of dampers is found by simulating the structural response to a white noise ground motion. A number of equivalent damping units with amplifiers are obtained assuming equal energy dissipation at minimum amplifying ratio. The effectiveness and performance of the proposed method are further demonstrated by simulating the response of the structure to natural earthquake records.