Forced Vibration Monitoring of Railway Bridges by use of Multiple Long Stroke Shakers

In this paper the potential application of multiple long stroke shakers to railway bridges is suggested to determine the natural frequencies and structural damping coefficients of railway bridges. In practice it is often observed, that the use of conventional monitoring methods, like ambient vibration monitoring, shows limits in the evaluation of realistic structural damping coefficients. By use of the proposed forced monitoring method by application of multiple long stroke shakers a sufficient vertical bridge vibration amplitude is generated and the values of determined structural damping become realistic. Hence, the identified dynamic parameters are ideal suited for the calibration of numerical bridge models. In the years 2016 and 2017 altogether 20 railway bridges with ballast track were measured in both, summer and winter conditions, by use of multiple long strong vibration exciters and the measuring results will be presented in this paper.