Vehicle-Based Indirect SHM of an Austrian Railway Bridge: Simulation and In-Situ Test

In recent years the application of vehicle-based indirect Structural Health Monitoring (SHM) to railway bridges has increased significantly and it has been shown that this method provides several advantages compared to traditional SHM methods. However, vehicle-based indirect SHM still entails several challenges that require further research. In this paper, the application of the vehicle-based indirect SHM method is demonstrated numerically and experimentally for determining the natural frequencies of an Austrian railway bridge. At first, the coupled equations of motion of the train-bridge multi-body model are presented and train crossing simulations are conducted numerically considering different train speeds. The vibration responses during train crossing are evaluated for both the train multi-body system and the considered railway bridge model. Different representative evaluation points are chosen at the wheelsets, bogies, and car bodies of the considered train. At second, the resonance frequencies of the bridge are measured in-situ by executing forced vibration tests applying closed-loop controlled electrodynamic shakers. Besides in-situ measurements of the bridge, the considered moving train is also equipped with accelerometers, and the vibration responses of both the bridge and the moving train are measured simultaneously during the duration of several train crossings. The recorded vibration responses are analyzed in the frequency domain and compared with the numerical simulation results. It is shown that the first longitudinal bending frequency of the considered railway bridge can be clearly identified from the computed frequency response spectra.