Response of a Roadway Lying on an Elastic Foundation to Random Traffic Loads

Abstract

This paper analyzes the response of a roadway lying on a Westergaard foundation to the pressures of a load moving on a random profile at a constant velocity. The profile power spectrum is based on experimental recordings done on French roads. From the vibrating axle characteristics, we may deduce the power spectrum of the exciting load. Then, we examine random bending vibrations so as to determine the expected mean square displacements of the roadway. We compare the results obtained for random and harmonic profiles. We notice that with the hard rubber foundation, mean values of deflections are comparable. On the other hand, with the soft rubber foundation, the displacement amplitudes for random excitation are much higher than results deduced for harmonic excitation. Consequently, it appears that with various isolation types, the sine profile is not sufficient to predict the roadway behavior. In fact, the actual behavior depends upon the profile power spectrum and vehicle characteristics.