Numerical Simulation of Rolling Dynamic Deflectometer Tests

Abstract

The responses of typical flexible and rigid pavements to the dynamic loads imposed by the rolling dynamic deflectometer (RDD) were investigated. The RDD is a recently developed nondestructive testing vehicle that applies a steady-state harmonic force while continuously moving along the pavement. To find the pavement response to moving harmonic loads, a numerical method using the elastodynamics solution for stationary impulsive loads applied to layered media and the superposition of the effect of sequential loading impulses at different stations (spaced according to the advance velocity of the load) was implemented. The effects of RDD velocity, loading frequency, depth to bedrock, and layer stiffness on the deflection basins were investigated in the longitudinal and transverse directions. The results show that for the vehicle velocities and loading frequencies that will be used in conjunction with the RDD, dynamic effects caused by the motion of the vehicle are negligible, and the deflection basins at any instant of time essentially are the same as those that would be obtained with a stationary static or harmonic load, with the advantage to RDD testing being that the loading magnitude and loading frequency can be changed easily and that profiling is continuous along the pavement.