Abstract

The Heavy Weight Deflectometer(HWD)/Falling Weight Deflectometer (FWD) plays a crucial role in assessing pavement’s structural condition. It consists of applying an impulse load to simulate a moving wheel and measuring pavement surface deflections. Pavement variables, such as moduli, are determined through backcalculation, which involves a forward model and optimization. The FAA currently employs static analysis in the BAKFAA software but encounters limitations, particularly with thick and stiff airfield pavements.

To address these challenges, a dynamic finite element (FE) model was developed under this study that incorporates subgrade damping to improve the reliability of backcalculation. The dynamic FE model was incorporated in a new tool called PULSE_FE to accelerate the computational runtime and improve efficiency. Dynamic backcalculation has been successfully applied to a Construction Cycle-9 flexible test item, and a parametric study has identified key FWD parameters for dynamic backcalculation.

Furthermore, an optimization framework was established to streamline the dynamic backcalculation process, seamlessly integrating modeling, FE analysis, and multiple optimizers. Constrained optimization was employed to enhance the practicality of solutions. Additionally, a user-friendly graphical user interface (GUI) program for BAKFAA Dynamic Backcalculation (DynaBAKFAA) was designed to simplify the tasks from mesh generation to dynamic backcalculation.

In summary, this project introduces a proficient FE model, advances in dynamic backcalculation, and an automated optimization framework, all poised to enhance pavement assessment and analysis. These developments are supported by a user-friendly interface designed for practical use.