Effects of Non-Linear Thermal Stress on Fatigue Damage of Airport Concrete Pavements

Thermal stress caused by temperature distribution in concrete slab is important in the structural design of airport concrete pavements. Airport concrete pavement slab is very thick, therefore, temperature in the slab varies nonlinearly throughout the slab depth. In this study, a method for estimating thermal stress in a concrete slab with 3DFEM analysis and heat transfer analysis was developed. The thermal stresses for airport concrete pavements with various thicknesses and climate conditions were calculated with the method for one year period and relative frequency distributions (RFDs) of the thermal stresses were obtained. Influence lines of load stress due to aircraft gear were also calculated with 3DFEM. The fatigue damages were estimated from the RFDs, the lateral distributions of the gear, combined stresses and fatigue curve of concrete. Based on the results, effects of the nonlinearity of thermal distribution and air temperature on the fatigue damage of airport concrete pavements were investigated in terms of the optimal thickness of concrete slab.