Evaluation of Frequency Content of Accelerations Recorded on Trains Crossing Multi-span Bridges

Abstract

The literature on drive-by methods that aim to estimate the dynamic properties of bridges from the acceleration response recorded on the vehicle is generally limited to highway bridges, with few studies focusing on railway bridges. Railway bridges provide an additional level of complexity to the problem because of the multifaceted nature of the railway track, which is likely to contaminate the response measured on the train with its own dynamic response. This article investigates the frequency content of the acceleration response recorded at different locations on a train that is traversing a multi-span bridge with the overarching goal of identifying the bridge frequencies. A detailed threedimensional model of the bridge that can capture the vibration characteristics of the bridge, track and the train is created and each component of the model is separately validated. The acceleration response recorded on front and back bogies and the middle of the train car under different velocities is studied to evaluate the presence and visibility of the bridge frequencies in this response. The results show that, in addition to track irregularities, the fundamental frequency of the bridge and the location of the sensor on the train play a significant role in identifying the bridge frequencies using drive-by methods.