To determine the influence of dynamic loading on pavement response, an analytical and a laboratory study were undertaken. In the analytical study, temporal and spatial variation of stresses and deformations in a pavement system, resulting from dynamic loading conditions, were estimated using the computer program SAPSI. To compute these stresses and deformations, elastic and damping characteristics of various materials constituting pavement sections were defined by a laboratory investigation that provided such data for an asphalt concrete (AC) and a fine-grained soil (silty clay) for a limited range in service conditions. With the SAPSI program, a representative pavement system consisting of an AC layer resting directly on silty clay subgrade was analysed to determine the pavement life that might result using actual load histories for three tandem-axle suspensions as compared to that obtained for the same axle with a uniform static load. Results of the dynamic analyses suggest that pavement life is reduced when dynamic effects are considered, and the magnitude of reduction is dependent on the tandem-axle suspension. The largest reduction in pavement life was obtained for the axle with the walking beam suspension. Comparable smaller reductions, as compared to the static case, were obtained for the torsion bar and four-leaf spring suspensions.
Samenvatting