Impact of non-uniform aircraft tire pressure on airfield pavement responses

Due to the continual loading of flexible airport pavements with heavy and wide-bodied aircrafts, it is crucial to consider the impact of aircrafts' tire pressure on pavement damage. The measurements in previous literature have shown that the distribution of tire contact stresses under heavy aircraft is highly non-uniform. Therefore, this study developed a three-dimensional (3-D) finite element (FE) model to investigate the effect of non-uniform aircraft tire pressure on airfield pavement responses. An existing asphalt pavement section at the National Airport Pavement Test Facility (NAPTF) was used in the analysis. The FE model characterized the hot-mix asphalt (HMA) layer as a viscoelastic material and utilized an implicit dynamic analysis to predict the time-dependent pavement responses under moving aircraft tire loading. The tire loading was simulated as a continuously moving load having half-sinusoidal shape distribution along the contact length and non-uniform distribution along five ribs of the tire. The pavement responses (tensile and shear stresses/strains) under various tire pressure distributions were calculated and compared. The results showed that the non-uniform aircraft tire pressure increases the longitudinal tensile strains at the bottom of the HMA layer and the shear strains/stresses in the HMA layer, compared to the traditional uniform tire pressure distribution. The non-uniform contact stresses at high tire inflation pressure resulted in high shear stress near the pavement surface that could cause primary rutting or near-surface cracking; this shows the importance of establishing guidelines for asphalt mixtures stability when used for airfield pavements that support relatively heavy aircraft.