Numerical iterative analysis for vehicle-bridge dynamic interaction

An uncoupled formulation of the equations of motion was previously proposed by the Au-thors to solve the problem of bridge-vehicle dynamic interaction in time domain, retaining a sufficient generality in modelling the subsystems, and including the effects of the pavement roughness. Based on this formulation, two iterative procedures have been developed and coded, differing in the iteration scheme. The first procedure analyses separately the two sub-systems over the whole time history (WTH) and relies on a general purpose FE code for the structure. The second procedure analyses the two sub-systems at the same time and within the same code. Iteration is performed on each single time step (STS), according to a predic-tor-corrector scheme implemented in an ad-hoc code. Aim of this work is to perform a com-parison of the numerical results of the two procedures in the same case-study, concerning a 30.3m long RC bridge travelled by a prototype vehicle. The time histories of the midspan displacement and of the contact force at one wheel are assumed as significant response pa-rameters. Two 3D FE models, characterized by the same discretization, are adopted for the bridge. The test vehicle travels on the bridge at different speeds and is described with a 7-DOF lumped parameter model. First of all the WTH procedure is validated against a closed form solution for the case of a sinusoidal roughness profile. Then, the comparison is per-formed for the cases of a smooth pavement and of a bump at the bridge entrance. A very good agreement is found in the first case, while some discrepancies appear in the second one.