Study of the Strain Response of Asphalt Pavements on Orthotropic Steel Bridge Decks through Field Testing and Numerical Simulation

A composite structural system consisting of an orthotropic steel bridge deck, waterproof prime, binding course, and wearing surface is complicated. To simplify the analysis of such systems, general elastic and continuous structure theory is applied to the asphalt pavement on steel bridge decks to determine the magnitude of the strain. Large differences in mechanical results have been previously obtained in assessments of steel bridge deck pavements. Few studies have focused on the mechanical state and time-dependent response of a realistic steel bridge deck wearing surface because of the difficulty of measuring the strain of the pavement on a steel deck of a long-span bridge that is in service. This study performed static and dynamic loading tests on an actual long-span steel bridge and analyzed the characteristics of the time-dependent strain response of the bridge deck wearing surface. The results demonstrate that the asphalt wearing surface exhibited significant loading time and rate-dependent characteristics under both static and dynamic loading conditions. The test analysis results also revealed that the axle load, vehicle speed, and longitudinal slope of the bridge had significant effects on the mechanical responses of the bridge deck wearing surface. Based on a comparison between the finite element numerical simulation results and the measurements obtained from testing the actual bridge, the magnitudes of the mechanical strain responses of the wearing surface on a steel bridge deck under the dynamic wheel load of a vehicle were analyzed assuming that the wearing surface is elastic and that the elastic modulus can be determined from a four-point bending test. However, the cumulative effect of plastic deformation must be considered when analyzing the fatigue damage of a permanent wearing surface.