Mechanistic models to predict structural performance and deterioration have been developed for both flexible and rigid pavements. However, many of these models retain a simplified and idealized depiction of tire loads, and none really incorporates a true representation of a moving, dynamic force along the pavement surface. Thus, attempts to model the impacts to pavements of new types of heavy vehicleshave at best been approximate and have often had to be supplementedby empirical data. In this paper we develop analytic models to study the interactions between moving, dynamic loads and highway pavements. One set of models simulates the dynamic behavior of heavy vehicles, including their body configuration and mass distribution, axle spacing and configuration, nonlinear suspension characteristics, and nonlinear tire behavior. The second set of models simulates the primary responses (stresses, strains, etc.) Of pavements to vehicle forces, and translates primary responses into pavement damage. Existing mechanistic models are modified specifically to treat moving, dynamic loads for both flexible and rigid pavements. This paper presents examples of results (in terms of both dynamic forces and pavement damage) for rigid pavements, although the concepts apply as well to flexible surfaces. A parametric study is summarized, considering variations in both vehicle and pavement characteristics. Those characteristics most important to dynamic loading include vehicle suspension type and characteristics, speed, height of pavement faults, and joint spacing. Other factors (such as tire pressure) contribute smaller effects (although tire pressures are more important on flexible pavements). Results indicate that under certain conditions, dynamic loads are 40% higher than static loads and affect the mid-region of pcc slabs most significantly. This paper appears in transportation research record no. 1196, Pavement evaluation and rehabilitation.
Abstract