Random Vibration Analysis of Dynamic Vehicle-Bridge Interaction Due to Road Unevenness

Abstract

Vehicle-bridge interaction has been studied for a long time to investigate the structural behavior of bridges and vehicle ride comfort. An original frequency domain method is presented where the vehicle-bridge interaction problem is solved in a frame of reference that moves with the vehicle. The Fourier transform of the interaction force is computed directly from the vehicle compliance and bridge compliance, without requiring any iterations. The method is particularly useful when a closed-form solution of the bridge compliance is available, as in the case of a simply supported Euler-Bernoulli beam model for the bridge. The solution is, therefore, well-suited for parametric studies on the bridge and vehicle response characteristics and offers a reference for more detailed models of the bridge and the vehicle or more complicated bridge configurations (e.g., continuous beam on multiple supports). The frequency domain approach also leads to enhanced physical understanding, because it shows how the interaction force decomposes into a term resulting from the dynamic response of the bridge to the constant moving load component and a term because of road surface unevenness. An efficient solution procedure based on random vibration analysis is presented, which allows for the computing of the statistical characteristics of the bridge and vehicle response from the power spectral density function of the unevenness. The procedure is validated by means of Monte Carlo simulation results for the case where the passage of a heavy vehicle on a highway bridge is considered.