3-D FE Analyses of Test Road Structures – Comparison with Measurements

Abstract

Two typical low volume Icelandic road structures have been tested in accelerated testing by using a Heavy Vehicle Simulator (HVS). Both were surface dressed structures, one with a 20 cm thick unbound base course layer and the other with the base divided into a 10 cm bitumen stabilized base over 10 cm unbound base. The test road structures were instrumented to estimate deflections, strains and stresses in various locations in the pavement structure. Elastic response analysis, by using a 3-D finite element (FE) technique, was carried out to simulate the tested structure and compare it with the actual measurements. The elastic stiffness moduli were entyrely derived from plate load test (PLT) results. The comparison of stresses showed relatively good correlation in the subbase and the embankment. However in the base course deviation occurred between the numerical analyses and the measurements, which increased as tyre pressure increased. This was probably due to the nonlinear behaviour of the base, which was not taken into account in the linear elastic analyses. Surface deflection measurements under the wheel load on the other hand gave lower values than the numerical analyses, which it should not if nonlinear behaviour in the base took place.