Influence of acceleration and deceleration of Super Heavy Loads (SHLs) on the service life of pavement structures

Abstract

Super Heavy Load (SHL) vehicles typically consist of heavy axles that impart substantial damages on transportation facilities such highway pavements and bridges. The taxing loading conditions, when combined with acceleration and deceleration forces from SHL vehicles, results in substantial interfacial shear stresses that manifests itself in premature failure of transportation facilities. This was the motivation for our research team to explore the detrimental effects of the acceleration and deceleration on the service life of roadways. To achieve this objective, our research team, initially deployed portable Weight-in-Motion (WIM) devices to ten sites with high frequency of SHLs in overload corridors of east and southeast Texas. Subsequently, nondestructive field tests such as Falling Weight Deflectometer (FWD) and Ground Penetrating Radar (GPR) were performed during summer and winter months for the back-calculation of the layer moduli in ten sites. The field observations and measurements were in turn incorporated in a three-dimensional (3D) finite element code for characterization of the influence of the acceleration and deceleration on the mechanical responses of the pavement structures. Then, a series of scenarios consisted of different patterns of acceleration, and deceleration were simulated in the 3D finite element software for ten sites and the results were contrasted with the steady rolling conditions. The sensitivity analyses of the representative pavements sections in this study showed that the deceleration or braking forces from the SHL vehicles resulted in the development of significant shear stresses in surface layers of thin structures. The stresses imparted by sudden changes in the velocity of super heavy vehicles can potentially jeopardize the longevity of the pavements structures and result in premature failure of transportation facilities. Therefore, analysis of acceleration and deceleration of the SHL vehicles should be an integral component in risk management studies of overload corridors.