| Nonlinear three-dimensional (3-D) dynamic finite element (FE) analyses are carried out to examine the structural performance of a pavement foundation system with and without the presence of geosynthetic reinforcement. Preliminary analyses are aimed at constructing a realistic finite element model representing a conventional pavement system in terms of geometry, loading system, boundary conditions and materials mechanical behavior. The dynamic implicit mode is used to handle dynamic equilibrium equations of the pavement system under traffic triangular wave load. Different strategies and provisions are made for considering the domain dimensions, choice of mesh and the constraints. In these preliminary analyses, the asphalt concrete (AC) viscoelastic behavior, the elastoplastic and elastoplastic strain hardening behavior of the base and subgrade, in addition to the linear elastic material of each layer are all covered in details and tested for the suggested finite element mesh. As a result of such analyses, a linear elastic asphalt concrete layer resting on a Drucker-Parger granular base underlined by a Cam Clay subgrade are adopted for conducting the parametric studies for reinforced and unreinforced conventional pavement systems. For the unreinforced systems, the results show that the subgrade strength has a significant effect on the pavement system rutting and little effect on its fatigue For the geosynthetic reinforced pavement system analyses, it is found that the geosynthetic placed at the bottom of AC leads to the highest fatigue resistance. (Abstract shortened by UMI.)... |
