Surface moduli determined with the falling weight deflectometer used as benchmarking tool

Abstract

A semi-mechanistic semi-empirical analysis technique has been developed in South Africa whereby deflection bowl parameters, measured with the falling weight Deflectometer (FWD), are used in a relative benchmarking methodology in conjunction with standardised visual survey methodology to give guidance on individual layer strengths and pinpoint rehabilitation needs. This benchmarking methodology can be enhanced by the use of calculated surface moduli based on the use of Boussinesq's equations. The calculation of such surface moduli can be enhanced by determining the gradient of the surface moduli an correlated with the subgrade layer and the elastic response characteristics. Such benchmark calculations are done without complicated and detailed multi-layered linear elastic modelling and software and enables the determination of the relative structural condition of pavement without detailed as-built data being required.