DEVELOPMENT OF A COMPUTER PROGRAM FOR DESIGN OF PAVEMENT SYSTEMS CONSISTING OF LAYERS OF BOUND AND UNBOUND MATERIALS. FINAL REPORT

A nonlinear finite element program (MICH-PAVE) has been developed for use on personal computers to aid in the routine design and analysis of flexible pavement structures. Three major achievements have been accomplished in this research. First, a new concept of utilizing a flexible boundary in pavement analysis has been introduced, and its characteristics fully investigated. Second, an extremely "user-friendly" nonlinear finite element program for pavement analysis and design has been implemented on personal computers. Third, two empirical equations to predict fatigue life and rut depth have been developed for use with nonlinear finite element analysis. In the MICH-PAVE program, the pavement is represented by an axisymmetric finite element model, and the resilient modulus model together with the Mohr-Coulomb failure criterion is used to characterize the nonlinear material response of granular and cohesive soils. Extrapolation and interpolation techniques have been used to improve stresses and strains at layer boundaries. Results from a variety of analyses have been compared with exact solutions (when available), and with the results from existing computer programs. Extensive sensitivity analyses have also been performed to explore the capabilities and limitations of the program.