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PROCEEDINGS OF THE ELEVENTH INTERNATIONAL CONFERENCE ON CIVIL, STRUCTURAL AND ENVIRONMENTAL ENGINEERING COMPUTING
Edited by: B.H.V. Topping
Vibration Control of High-Speed Railway Bridges using Viscoelastic Dampers
E. Moliner1, M.D. Martínez-Rodrigo2 and J. Lavado1
1Structural Mechanics and Hydraulic Engineering Department, University of Granada, Spain
E. Moliner, M.D. Martínez-Rodrigo, J. Lavado, "Vibration Control of High-Speed Railway Bridges using Viscoelastic Dampers", in B.H.V. Topping, (Editor), "Proceedings of the Eleventh International Conference on Civil, Structural and Environmental Engineering Computing", Civil-Comp Press, Stirlingshire, UK, Paper 50, 2007. doi:10.4203/ccp.86.50
Keywords: high-speed railway bridges, retrofit of bridges, ballast instability, viscoelastic dampers, resonance phenomena, moving loads, Kelvin solid model.
In the present study a procedure to dimension the retrofitting system for high-speed railway bridges using discrete viscoelastic dampers (VEDs) is devised and verified with a representative numerical example.
Viscoelastic dampers have been used for vibration mitigation in structures for many years . Most often these devices have been used for controlling wind-induced vibrations in tall buildings, and to dissipate the seismic energy input in structures subjected to earthquakes, and its effectiveness has been demonstrated both experimentally and analytically by many researchers over the past decades.
The configuration of the proposed damping system proposed in this work is similar to the one presented in the previous work of Museros and Martínez-Rodrigo . In a first approximation, the bridge is modeled as a simply supported Euler-Bernoulli beam. This simplification is valid for single track non-skewed bridges whose response is mainly governed by flexural modes. The main beam, which represents the bridge response, is connected to an auxiliary beam using a series of discrete VEDs, modelled by Kelvin elements.
The dynamic behavior of a given unretrofitted bridge is computed under the circulation of several train models in order to obtain the maximum vertical acceleration in the main beam and to estimate the amount of damping required to satisfy the serviceability limit state of the vertical acceleration of the deck.
Applying the dimensioning procedure of the retrofitting system, a proper combination of VEDs and auxiliary beam is selected for this given bridge such that the required global damping ratio for the structure is obtained. Finally, the response of the bridge equipped with the damping system is analyzed with a view to discovering whether the accelerations satisfy the serviceability limits, and the retrofitting system is redimensioned if necessary.
It can be concluded that the vertical acceleration of the brige can be suitably reduced with the proposed damping system.
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