Simulation-based load distribution behaviour of a steel girder bridge under the effect of unique vehicle configurations

A better understanding of load distribution behaviour resulting from varying vehicles is needed for the reliable structural integrity assessment of existing bridges. The main focus of this study is on the exploration of the influence of unique vehicle configurations on load distribution factors of a steel bridge on rural roadways where different distinctive farm vehicles frequently travel. The steel girder bridge located in the USA was used and modelled in commercially available finite element software. Field data obtained from live load tests were utilized to calibrate the model. A large number of existing vehicles commonly used for agricultural purposes were collected and applied to the model in order to capture the simulated strain responses necessary for the calculation of load distribution factors for interior and exterior girders. Analytical distribution factors for varying vehicles with different transverse vehicle positions were plotted on scatter graphs and evaluated for the effects of vehicle characteristics on their distribution factors. To evaluate their reasonableness, the simulated factors were compared to those obtained from the field tests and the American Association of State Highway and Transportation Officials (AASHTO) Standard and load and resistance factor design (LRFD) specifications. Findings indicated the level to which vehicle characteristics had a great impact on analytical interior and exterior load distribution factors and some distribution factors that were computed exceeded both the AASHTO Standard and LRFD code limits.