Multi-wheel gear loading effect on load-induced failure potential of airfield flexible pavement

Abstract

ABSTRACTThis study aimed to investigate the effect of multi-wheel loading gear configuration on loading-induced failure potential of airfield flexible pavements. Field response testing was conducted in the National Airport Pavement Test Facility (NAPTF) using different multi-wheel gear configurations. Three-dimensional (3-D) finite element (FE) models were developed to simulate multi-wheel loading along with non-uniform tyre contact stresses. The 3-D FE models were validated by tensile strains measured from response testing. The effects of wheel loading configurations and magnitudes on different strains responses were compared for two pavement sections with different asphalt layer thicknesses. Analysis results showed that six-wheel gear configuration caused the greater pavement responses. The critical shear strains were found greater than critical tensile strains at the same loading condition and pavement structure, especially for thick asphalt pavements. This is consistent with top-down cracks observed at field sections after traffic testing. On the other hand, shear strains increase more rapidly as the load level increases as compared to tensile strains; while thin asphalt layer is more sensitive to loading magnitude as compared to thick asphalt layer. The multi-wheel effect on fatigue life is more significant for thick pavement due to the load superposition effect under different wheels.