Effect of Finite Width on Dynamic Deflections of Pavements: Fid-Bau Portal

Effect of Finite Width on Dynamic Deflections of Pavements

Y. V. Kang / J. M. Roesset / K. H. Stokoe

A highway has a finite width in its transverse direction, and the existence of variation in material properties between the road and the surrounding soil is not uncommon. A three-dimensional elastodynamic solution is presented to take into account the variation of material properties in the soil-pavement system by using the Fourier superposition technique. The pavement, base and subgrade are represented by a finite-element core region. An expansion technique is used to simulate the infinite lateral soil region. A viscous boundary is implemented for a half space condition. The stiffness matrices and point load and disk load vectors are obtained in the frequency-wavenumber domain. Parametric studies of the soil-pavement formulation are conducted to assess the accuracy of the results. An investigation of the effects of the lateral boundary on the pavement deflections measured by various nondestructive testing techniques is presented. The Dynaflect, the Falling Weight Deflectometer (FWD), and the Spectral-Analysis-of-Surface-Waves (SASW) methods are simulated on three typical in-service pavement sections. The results of the Dynaflect tests indicate that the effects of the lateral boundary on the measured deflections are directly related to: (1) the loading position with respect to the edge of the pavement; (2) the thickness of the surface layer; (3) the lateral stiffness contrast between the road and the surrounding soil; (4) the height of the ramp, if the test is performed on a ramp. A closer loading position, a larger value of the thickness, a higher contrast, and a larger value of the ramp height will result in a larger influence on the deflections.