Damping Assessment on Railway Bridges Based on an Extensive Experimental Database Framed on the InBridge4EU Project

The structural damping on railway bridges has a very significant effect on the dynamic response at resonance when the loading frequency of the train, or a multiple of, matches the natural frequency of the bridge.However, its estimation is not straightforward, since the literature points to a large scatter in damping coefficients even in similar structures.To tackle the issues associated with this important factor in the evaluation of the effects caused by the bridge vibration under railway traffic, the European Union Agency for Railways (ERA), together with the Europe's Rail Joint Undertaking (EU-Rail), launched a European call for a project whose main objectives consisted on proposing recommendations for improving the current standards that deal with bridge dynamics, namely EN1990-A2 and EN1991-2.In this sense, the project InBridge4EU aims to answer these questions by studying, among other normative topics, the damping on bridges and its normative values currently specified in EN1991-2.This paper presents, therefore, the first results obtained from several measurements carried out in Portuguese and German bridges using the Covariance Driven Stochastic Subspace Identification (SSI-COV) method, including a preliminary analysis of the factors that might influence the damping scatter.