Control of wind induced buffeting vibrations in a long span suspension bridge by TMDs

Abstract

Wind buffeting is regarded as one of the most important dynamic excitations for long span flexible bridges owing to the low frequency content which characterizes its spectrum. In this paper a suspension bridge model with steel frame deck, is considered as a case study for performing numerical simulations and evaluating suitable control strategies for mitigating dynamic vibrations induced by strong wind loading. Structural control can effectively contribute to satisfy the high standard of performance, feasibility and safety that long-span suspension bridges are expected to show. In this light, passive, semi-active and hybrid control strategies are implemented within the research work, described in this paper, for alleviating buffeting dynamic effects on the bridge model. Optimal tuned mass damper solutions are firstly evaluated by using a simplified two degree of freedom structural model. Subsequently their efficacy has been tested on the whole bridge finite element model at the deck mid-span. Such a passive control strategy is finally coupled and compared with passive and semi-active hysteretic dampers connecting the deck and the piers. The proposed control strategies are shown to significantly reduce the value of the structural response in terms of internal forces, and displacements as well as, intending to be consistent for real implementations on new and existing suspension bridges. © Civil-Comp Press, 2013