Seismic control of continuous bridges using variable radius friction pendulum systems and viscous fluid dampers

This paper investigates the performance of a variable radius friction pendulum system (VRFPS) with supplementary damping using viscous fluid dampers (VFD) to control the seismic response of bridges. A VRFPS is similar to a frictional pendulum system (FPS), but the curvature of the sliding surface is varied, and it becomes the function of the sliding displacement. The bridge is seismically isolated with a VRFPS between the superstructure and the pier, and a VFD is added between the abutment and superstructure. Effectiveness of the proposed system is studied for a three-span continuous bridge isolated with a VRFPS and VFD hybrid system. The performance of a proposed system is compared to a corresponding performance of a hybrid system consisting of a conventional FPS with a VFD. The results of the numerical simulation showed that supplementary damping reduces the seismic response of the isolated bridge. Further, a hybrid system consisting of a VRFPS and a VFD is found to be more effective than a FPS and a VFD hybrid system for seismic control of bridges.