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-bridg e systems. With the finite-element method, a vehicle is modeled as lum ped masses supported by springs and dashpots, and a bridge with rough pavement by beam elements. An interaction element is defined to consis t of a bridge element and the suspension units of the vehicle resting on the element. The composition of an interaction element and the part s of car bodies in contact is regarded as a substructure. By the dynam ic condensation method, all the degrees of freedom associated with the car bodies existing within each substructure are eliminated. As the c ondensation has been performed on the element level, a conventional as sembly process can be applied to form the structural equations. Compar ed with most existing procedures, the present technique appears to be computationally more efficient. It is particularly suitable for the si mulation of bridges with a series of vehicles moving at different spee ds and/or directions.