Performance of multiple tuned mass dampers for suppressing buffeting response and increasing flutter speed of long-s-pan bridges

performance of multiple tuned mass dampers (MTMDs) for suppressing buffetin g response and increasing the critical wind speed of long-span bridges is e xamined. In this model, each damper is positioned at a distance from the de ck center, and corresponding to it, there is an identical damper in the opp osite direction to make this system balance. The vertical and torsional dam pers are tuned at the frequencies of the first vertical and torsional struc tural modes, respectively. The performance of vertical dampers is not I-ela ted to their locations. However, the performance of torsional dampers is st rongly dependent upon their level arms to provide torsional damping and sti ffness. Using both vertical and torsional dampers, the vertical and torsion al buffeting responses can be reduced and the stability of the bridge can b e increased fur either single-degree-freedom flutter or coupled flutter. A parametric analysis is used to study the performance and characteristics of the MTMDs, and based on these results, the design parameters including mas s, damping, frequency bandwidth, lever arm, and total number of TMDs are pr oposed. The results also indicate that the MTMDs, designed with the recomme nded parameters, are not only more effective but also more robust than the usual single TMD against wind-induced vibration.