Smart Damping Strategy of Seismically Excited Cable-Stayed Bridges Using MR Fluid Dampers

This paper proposes a new smart damping strategy for seismic protection of cable-stayed bridges, focusing on inclusion of effects of control-structure interaction, by examining the ASCE first generation benchmark control problem for a seismically excited cable-stayed bridge. Magnetorheological (MR) fluid dampers, which belong to the class of controllable fluid dampers, are the supplemental damping devices proposed for this study, and a clipped-optimal control algorithm, shown to perform well in previous studies involving MR fluid dampers, is employed. A modified Bouc-Wen model, which is obtained from the comprehensive investigation of the full-scale MR fluid damper, is considered for the dynamic model of the MR fluid damper. Because the MR fluid damper is a controllable energy-dissipation device that cannot add mechanical energy to the structural system, the proposed control strategy is fail-safe in that bounded-input, bounded-output stability of the controlled structure is guaranteed. Numerical simulation results show that the performance of the proposed semi-active control strategy using MR fluid dampers is quite effective