Near Surface Pavement Response Using a Numerically Approximated Tire Contact Pressure From Inverse Analysis

Abstract

Current military flexible pavement design is based on a mechanistic–empirical methodology, in which the mechanistic response is sometimes computed using a layered elastic analysis (LEA) approach. The assumption in most LEA computer programs is that the load is applied uniformly over a circular contact area. In most cases where subgrade rutting failures are expected, this assumption provides satisfactory results when the responses are computed in the subgrade far from the applied load. But in the case of thin asphalt structures with marginal base materials, base failures could potentially occur and the effects of nonuniform tire contact pressure could be more prominent. This study presents a numerical approximation method of obtaining a possible nonuniform, noncircular tire contact pressure distribution using the LEA framework. The iterative procedure attempts to match the true contact area and satisfies the requirements of static equilibrium using inverse analysis. The results showed that the numerical approach provided more reasonable near surface responses compared with the uniform contact pressure assumption and was noticeably more efficient than its finite element counterpart. The findings suggested that the numerical procedure could provide a sound mechanistic alternative for designing thin asphalt pavements with marginal base materials where base failures are likely to occur.