Multiple Wheel–Load Interaction in Flexible Pavements

Abstract

Various highway vehicle axle–wheel arrangements and aircraft gear–wheel configurations adopted currently to accommodate increasing load levels affect, according to different multiple wheel-loading scenarios, flexible pavement response and performance. The traditional approach of single wheel–load response superposition, especially in the case of nonlinear analysis, may not be adequate to analyze pavements subjected to such multiple wheel-load cases. These complex loading conditions require advanced pavement layered solutions for realistic consideration of nonlinear behavior of pavement foundation geomaterials (e.g., fine-grained subgrade soils and unbound aggregates used in untreated base–subbase layers), and at the same time use three-dimensional (3-D) finite element (FE) analyses to apply multiple wheel loading. In this study, stress-dependent resilient modulus models successfully incorporated into the 3-D FE-based mechanistic pavement analysis through a programmed user material subroutine in ABAQUS were used to predict pavement resilient responses at observed critical-load locations. The results indicated that proper characterizations of the nonlinear, stress-dependent pavement foundation geomaterials significantly affected predictions of critical pavement responses. Most important, pavement responses under multiple wheel loads were somewhat different from those obtained from the single wheel–load response superposition approach, which suggested the need for 3-D nonlinear FE analyses for improved response predictions.