Identification Method of Bridge Influence Line Based on Dynamic Response of Passing Heavy Vehicle

Bridges play a crucial role in transportation systems. Therefore, it is necessary to evaluate the health conditions of bridges owing to damage and deterioration during long-term operation. In addition to bridge modal parameters, the influence line of a bridge is required for bridge condition evaluation. Bridge displacement or strain induced by a moving inspection vehicle is typically adopted in conventional methods to extract the influence line of a bridge; hence, sensors should be installed on the bridge, and traffic should be blocked during measurements. In this study, the coupling effect of heavy vehicles and bridges was investigated to derive the dynamic response of a heavy vehicle passing over a bridge. Moreover, a method for identifying the bridge influence line based on a weighted polynomial chirp-let transform was proposed, which was verified using numerical simulations and experiments. The proposed method uses the vertical acceleration of a passing heavy vehicle instead of the displacement of the bridge to extract the influence line of the bridge; therefore, it is a typical indirect method that can be easily implemented in practical applications. The numerical simulation results show that the analytical solution of the dynamic responses of the bridge and vehicle obtained in this study is more accurate than the classical solution in which the coupling effect of the vehicle and bridge is ignored. The passing vehicle is simplified as a moving constant load, and the bridge influence lines can be identified accurately using the proposed method. The experimental results show that the proposed method performs satisfactorily at different driving speeds and vehicle masses. © 2024 Chang'an University. All rights reserved.