Dynamic Performance of Existing High-Speed Railway Bridges Under Resonant Conditions, Retrofitted with Fluid-Viscous Dampers Supported on Clamped Auxiliary Beams

Abstract eng:
In this contribution the application of Passive Control techniques is applied to reduce the severe transverse vibrations that railway bridges of moderate lengths may experiment under resonance conditions. The proposed solution consists on connecting the slab to a series of auxiliary beams with partially restrained rotational end conditions through a set of fluid-viscous dampers. A particular configuration minimizing the space occupied under the bridge deck by the devices and the auxiliary beams is proposed for slabs and girder bridges, typical typologies in the aforementioned range of lengths. First, the dynamic response of the double-beam system at resonance is obtained in closed-form under harmonic excitation in order to detect the main governing parameters of the bridge response. Then conditions for the optimal dampers constants and minimum beam sizes that minimize the bridge dynamic amplification at resonance are obtained using a planar analytical model. Finally the effectiveness of the solution and the adequacy of the expressions derived from the harmonic case are proven under railway traffic excitation. Special attention is given to the beneficial effect of partially restraining the auxiliary beam supports throughout the study.

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