Effects of Nonuniform Tire Contact Pressures on Near-Surface Pavement Response

Abstract

Most current mechanistic-empirical (ME) design methodologies leverage layered elastic (LE) computer codes to compute pavement response at locations indicative of distresses. In conventional pavements, the subgrade is the layer of interest and the exact distribution of the contact pressures is of less consequence. However, in thin pavements or base layers with marginal materials in contingency airfields, rutting failures can occur in the base. Thus, the nonuniformity of tire contact pressure becomes increasingly important in determining near-surface response. While most LE formulations assume a uniform contact pressure, difficulties arise when using this approach to match near-surface stresses in instrumented test sections for nontraditional pavement structures. This paper describes the formulation of a nonuniform loading function implemented into an LE program and its comparison to measured field data. Results show that the nonuniform loading function provides a closer approximation to field data than the standard uniform pressure assumption typical in current design methodologies. Findings suggest that the ME design of contingency airfields should incorporate a nonuniform loading function to improve base layer rutting failure predictions.