Seismic Response Control for Bridge Piers with Semi-Active MR Damper Based on Displacement Feedback

This study investigates the semi-active control of railway bridges using an MR damper to reduce the excessive displacement in the bearings of isolated bridges under severe earthquakes. Within the study context, the variable-oval-control (VOC) rule based on structural response displacement feedback is applied to the MR damper and compared with a passive control and clipped optimal semi-active control algorithm. The simulation results show that the dynamic response of railway bridge piers can be effectively reduced, and seismic safety can be significantly improved using MR dampers based on a variable ellipse control strategy. MR damper, based on the VOC rule, directly adopts structural response displacement to perform control force state change. The VOC method only requires the minimum control force to achieve a good displacement control effect, high control efficiency, and stable control effect.