Control of Wind-induced Nonlinear Oscillations in Suspension Bridges using Multiple Semi-active Tuned Mass Dampers

Abstract

The effectiveness of using Multiple Tuned Mass Dampers (MTMD) to increase the critical wind speed of a flexible long span suspension bridge subjected to wind loading is studied. The mean wind direction is assumed to be perpendicular to the plane of the suspended cable. The along-wind response and across-wind response of the suspended cables and the bridge deck response due to wind are studied, and it is shown that using a single passive or semi-active tuned mass damper (STMD) with a large mass at the mid-span of the bridge raises the critical wind speed of the suspension bridge. As the installation of a single large passive or semi-active tuned mass damper is problematic, we investigate the effectiveness of using multiple tuned mass dampers (MTMD) with small masses located at various positions along the bridge deck. In order to further increase the critical wind speed, the passive MTMD are supplemented by velocity feedback active control forces. The effects of the dampers’ locations, the mass ratio and the damping ratio on the critical wind speed are also investigated.