Dynamic interpretation of dynaflect and falling weight deflectometer tests on pavement systems

The dynaflect and the falling weight deflectometer are commonly used for non destructive testing of pavements. Although in both cases a dynamic load is imparted, the determination of the mechanical properties of the pavement is normally performed by using static analyses. In this study, the displacements obtained from dynamic analyses are compared to those provided by conventional static programs when the subbase is a homogeneous soil stratum of finite depth, resting on a much stiffer rock like material and when the soil properties increase smoothly with depth, as is often the case. The results of these comparisons indicate that for certain ranges of depth to bedrock a static interpretation of the dynaflect and falling weight deflectometer tests may lead to substantial errors. Situations where these errors are important are more likely to be encountered with the dynaflect than with the falling weight deflectometer (a).