ABSTRACT
ABSTRACT: The goal of this paper is to present the details of an approach that can be used to evaluate the strain distribution in large-scale, geogrid-reinforced, unbound pavement test sections during application of dynamic surface loads. The approach is based on a 4-node isoparametric finite element formulation; wherein shear and normal strains are calculated from the response of geophones embedded in a reinforced pavement test section subject to different magnitudes of dynamic load. Details are provided on the construction of a large-scale reinforced pavement test section, application of dynamic surface loads using a Vibroseis (shaker) truck, instrumentation, and data reduction procedures used to obtain strain distribution as a function of depth. Results from the study show log-linear increases in shear and normal strain at all depths in the pavement test section as a result of increasing surface load amplitude. A reduction in the shear and vertical normal strains in the sub-base and subgrade layers (below the geogrid) from that measured in the base course layer was also observed. The preliminary results from this study indicate that the presence of the geogrid in the base course may contribute to a decrease in strains transmitted to underlying layers. Additional comparative studies using the testing approach described in this study are needed to confirm these findings.
