A Best-Fit Rigid Pavement Back-Calculation Method Based on Site-Specific FEM Analysis

This paper introduces an improved best fit back-calculation technique based on deflection predictions obtained using finite element method (FEM) simulations through EverFE of the actual slab configuration, rather than generic theoretical deflection predictions. It is based on minimizing the squared error between FWD measured deflections and FEM predicted deflections. It assumes that the modulus of the concrete is known, (i.e., it can be readily obtained through relatively inexpensive shear wave propagation techniques) and gives a closed-form solution for the modulus of subgrade reaction. The results of this method were compared to the ones obtained by the LTPP best-fit method, using as a reference the LTPP database subgrade reaction moduli values obtained from plate loading tests. The results suggest that the proposed method improves on the traditional best-fit back-calculation technique.