Effectiveness of 2D FDTD Ground Penetrating Radar Modeling for Bridge Deck Deterioration Evaluated by 3D FDTD

Computational modeling is effectively analyzes the wave propagation and interaction within bridge structures, providing valuable information for sensor selection and placement. It provides a good basis for the inverse problem for defect detection and reconstruction. The finite difference time domain (FDTD) method can be used to model nondestructive wave based sensing using air-coupled ground penetrating radar (GPR). A full 3D model is able to capture all interactions but is limited by computational size and CPU time. In contrast, a 2D model is computationally fast and capable of studying a large computational region, but lacks a complete view of the problem. In this study, we propose to use the 2D FDTD model to simulate the GPR detection of bridge deck defects. The effectiveness of the 2D model is validated by comparison to a full 3D model. The bridge deck is a relatively uniform in the transverse direction so that the 2D longitudinal geometry analysis can therefore adequately capture most of the 3D scattering behavior.