Semi-active control of bridges with use of magnetorheological dampers

This study was conducted to investigate the application of a magnetorheological (MR) damper in the semi-active control of bridge response. A series of cyclic loading tests was carried out on a MR damper under various loading frequencies, loading amplitudes, and current levels. The damping force of the MR damper was idealized by the model composed of friction and viscous elements in parallel. Two algorithms to change damping force according to displacement or velocity were investigated. It is found that the commanded damping force can be realized by the MR damper. However, discrepancy of damping force is observed, especially when the rate of change of the damping force is high. The shaking table test was conducted on a model bridge with the MR damper to investigate the effectiveness of the control algorithms.