Vehicle-Bridge Interaction Analysis by Dynamic Condensation Method

This paper is aimed at the development of a computationally efficient procedure for simulating the dynamic response of general vehicle-bridge systems. With the finite-element method, a vehicle is modeled as lumped masses supported by springs and dashpots, and a bridge with rough pavement by beam elements. An interaction element is defined to consist of a bridge element and the suspension units of the vehicle resting on the element. The composition of an interaction element and the parts of car bodies in contact is regarded as a substructure. By the dynamic condensation method, all the degrees of freedom associated with the car bodies existing within each substructure are eliminated. As the condensation has been performed on the element level, a conventional assembly process can be applied to form the structural equations. Compared with most existing procedures, the present technique appears to be computationally more efficient. It is particularly suitable for the simulation of bridges with a series of vehicles moving at different speeds and/or directions.