Efficacy of tuned mass dampers for bridge flutter control

This paper examines efficacy of tuned mass dampers (TMD) in controlling self-excited motion resulting from negative damping. New optimal TMD parameters are suggested which provide better performance than those suggested in the literature. The dependence of TMD performance on structural damping is highlighted. The equations of motion of a combined system comprised of multiple TMDs attached to a bridge deck are presented where the bridge motion is described in terms of reduced-order modal coordinates. Details concerning the multimode coupled flutter of long-span bridges with auxiliary TMDs are provided. The effectiveness and limitations of TMDs for controlling multimode bridge flutter are examined, emphasizing the dependence of TMD performance on the bridge dynamic and aerodynamic characteristics. This study shows that the effectiveness of TMDs is rather limited in controlling a hard-type flutter characterized by negative aerodynamic damping that grows rapidly with increasing wind speed beyond the onset of flutter. However, it is relatively effective in controlling a soft-type flutter in which the negative damping builds up slowly with increasing wind speed. Robust TMD design issues are also discussed in light of their sensitivity to design parameters in the vicinity of optimal values.