Issues in simulating falling weight deflectometer test on concrete pavements

Falling Weight Deflectometer (FWD) produces pavement responses using a falling mass drop. This study investigated the features involved in the finite element modeling of FWD tests to help in the calibration of backcalculation. Falling mass, model size, subgrade damping, and boundary conditions were studied to reveal the significances of these factors on pavement responses. By modeling the falling mass in finite element models, this study has justified the idea that field-measured time history of impact force can be used as an alternative to falling mass. It is also concluded that subgrade damping, self-weight of slab, and boundary conditions are significant in modeling and interpretation of FWD finite element analysis. Finite element model with at least six times radius of relative stiffness is required to simulate dynamic responses of a continuously reinforced concrete slab.