Numerical assessment of dynamic response of highway bridges subjected to heavy vehicles

This paper presents results of the Finite Element (FE) analyses of dynamic interaction between heavy vehicles and selected group of smaller, typical Florida highway bridges. Computational mechanics and LSDYNA, 3-D explicit, dynamic, non-linear FE code were used as primary research tools to investigate vehicle – bridge interaction. One selected vehicle-bridge configuration was thoroughly validated by conducting actual dynamic testing on a highway bridge on US 90 in Northern Florida. Collected experimental data, which included time histories of strains, displacements, and accelerations of selected points on the bridge and the truck, were found to be well correlated with computational mechanics analysis. Dynamic impact factors were calculated for over thirty vehicle-bridge cases based on FE models of one heavy truck, three cranes and four bridges. Influence of vehicle mass, their speed, bridge span lengths, and deck surface imperfections on bridge dynamic response was investigated using bridge and vehicle FE models developed. These validated models can be used for follow-up studies for other vehicle-bridge combinations in the future. It is expected that extrapolating results of FE analysis on a broad class of heavy vehicles and bridges will enable formulation of practical recommendations for management decisions regarding dynamic impact factors, speed limits, or permissible weight of the heavy vehicles for highway bridges.