Abstract

This paper studies the effect of vehicle-bridge interaction (VBI) on the vibration of the supporting bridge, and subsequently proposes a decoupled analysis scheme for the VBI problem with reference to high-speed railway systems. The study examines the VBI problem analytically and reveals the main coupling parameters between vehicles and bridges. It proves that, except for the stiffness ratio, the impedance ratio, defined as the ratio of the vehicle's damping and bridge's mechanical impedance, is also a dominant coupling parameter between vehicles and bridges. Following, the study shows that VBI alters the mechanical system of the bridge via an additional damping, an additional stiffness and a modified loading term. The coupling terms (i.e., the vehicle response) appear solely in the modified loading term. Assuming small stiffness ratio, which is realistic for practical train-bridge systems, the proposed decoupling scheme eliminates the vehicle response from the bridge's equation of motion in a systematic manner. With respect to the fully coupled system, the proposed method returns more accurate results compared to well-known decoupling methodologies, such as the moving load approximation.