Moving two-axle high frequency harmonic loads on axially loaded pavement systems

Abstract

The dynamic displacement response of axially loaded pavement models was investigated comprehensively when the system was subjected to two-axle moving harmonic loads whose frequencies were higher than the natural frequency of the system. The axially loaded beam on an elastic foundation was employed as a simplified pavement model under axial compression. The foundation was assumed to have damping of a linear hysteretic nature. Formulations were developed in the transformed field domains of time and moving space, and the steady-state responses to moving harmonic loads were obtained using a Fourier transform. The effects of various parameters, such as the load distance, load phase, axial compression, foundation damping, load velocity, and load frequency, on the displacement amplitude distribution and maximum displacement were investigated. The analysis results showed that the displacement responses were much affected by the load distance and load phase between two moving loads. For relatively low load velocities, the critical axial compression was dependent on the load distance and load phase, but for relatively high load velocities, it was not affected by them. There were two critical values of the load velocities and load frequencies. The second critical velocity and the first critical frequency were independent of the load distance and load phase; however, the first critical velocity and the second critical frequency were affected by them.