Assessment of the impact of layer moduli on measured surface deflections.

This paper deals with the interpretation of falling weight deflectometer test data, with emphasis being placed on presenting a methodology that can be used to determine the sensitivity of measured surface deflections to the location and stiffness of each layer in a pavement/subgrade system. It begins by introducing the notion of contribution ratio and then presents a theory, cast within finite element methodology, that is used to quantify deflection and strain field sensitivity to layer characteristics. Although the methodology applies to both elastostatic and dynamic analyses, emphasis is placed on the elastostatic responses. Unlike previous expositions, the authors make direct use of the definition of contribution ratio without having to deal with stochastic finite element modelling. Examples are presented and the authors demonstrate that the results from the analyses are consistent with experience. For the covering abstract of this conference see ITRD number E211271.