Airport Pavement Response under Moving Dynamic Aircraft Loads

The pavement responses have often been analyzed with static loads, but the pavement critical responses are induced by moving dynamic loads. The objective of this paper is to investigate the dynamic stress and displacement responses of rigid airport pavements subjected to moving dynamic aircraft loads with a constant advance velocity. The airport pavements have been modeled using a plate of infinite extent on a viscoelastic foundation. The moving aircraft loads have been generated considering a twin-tandem main gear with a constant load amplitude or harmonic amplitude variations. To find the pavement responses to moving loads, formulations have been developed in the transformed field domain using a double Fourier transform in space and moving space for the steady-state response to moving harmonic loads and moving loads of constant amplitude. The effects of viscous damping of underlying layers, aircraft speed, and load frequency on the maximum deflection and stress have been investigated. The deflection and stress distributions near the loads have also been studied. The analysis results considering viscoelasticity of the foundation show significant differences from those obtained with an elastic system. Without viscous damping, the effects of aircraft speed and load frequency, within practical ranges, on the deflection and stress are negligible; however, with viscous damping, those effects are significant. The phase between front and rear loads can significantly decrease the maximum deflection and increase the maximum stress.