Prediction of vehicle-induced local responses and application to a skewed girder bridge

This paper proposes an innovative and flexible simulation method that predicts the dynamic responses of bridges induced by passing vehicles. The decoupled equations of motion of the vehicle–bridge system are derived from Lagrange equations and include the effect of road surface roughness, while the interaction forces between the two systems are calculated step by step, using Newmark’s method. This algorithm does not require a special finite element (FE) code and can be implemented with standard FE software and general numerical software such as ABAQUS and MATLAB, respectively. In order to illustrate the practicability of the method, an extensive case study is then presented in which some aspects of the dynamic behaviour of a skewed bridge monitored under vehicle-induced loads are investigated. After adjustment of the boundary conditions and the spectral roughness coefficient, good agreement is obtained between the bridge vibrations predicted by the numerical model and the field measurements. The validated model is further used to analyse the distinctive dynamic effects caused by the skewness. For that purpose, a reference non-skewed bridge model is prepared according to the same design as the original skewed bridge. The obtuse corner of the skewed bridge located near the loading path is found to be a critical region where the slab-negative moments, the girder stress near the sole plate and the bearing force are significantly greater than those in the reference bridge.