Vehicle Bridge Interaction – Extracting the dynamic characteristics of the non-stationary train passing phase

Monitoring of bridge has received a significant amount of attention over the past years, as the condition of these infrastructure elements is crucial to guarantee uninterrupted traffic of people and goods between regions. Most monitoring systems identify the dynamic properties of the structure, such as the resonance frequency. The resonance frequency is however not the best measure for the presence of damage. Moreover, in case the dynamics of the passing vehicle interact significantly with the dynamics of the bridge, the analysis becomes complex. Often, only the free vibration is used. Here, the Wavelet-based Synchro-Squeezed Transformation is proposed as a method to extract the instantaneous resonance frequency of the vehicle-bridge system. This allows to eliminate both operational and environmental influences. Analysis on a numerical model reveals that the method has potential to be a more robust in the identification of damage in bridge-like structure passed by a relatively heavy vehicle. A first validation based on field measurements on Irish Boyne viaduct support the capabilities of the method as predicted by the results of the numerical model.