Verification of falling weight deflectometer backanalysis using a dynamic finite elements simulation

Falling weight deflectometer (FWD) testing is probably the most widely used device for the non-destructive testing of pavements. In many cases, engineers use the FWD test data for the estimation of pavement material properties, assuming a quasi-static approach. Since the verification of such results is often necessary, a dynamic finite element (FE) approach can be used towards this goal. Analytically, data provided by static backanalysis is used as input for 2D and 3D dynamic FE modeling of the FWD test in order to calculate the expected deflection bowl. Comparison of the measured with the calculated deflection bowl may provide a strong indication for the validation of the backanalysed data. Investigation of the application of this approach using field data from new and existing asphalt pavements with two different FWDs and several backanalysis programs as well as data of laboratory tested cores is also presented and discussed.