Evaluation of layer properties of flexible pavement using a pseudo-static analysis procedure of Falling Weight Deflectometer

Most backcalculation programs used to evaluate the pavement layer properties assume static deflections even though dynamic deflections are generated from the Falling Weight Deflectometer (FWD). This study aims to take into consideration the dynamic effects of the deflection basin from the FWD in the backcalculation procedure. A Pseudo-static backcalculation procedure, named DYN-BAL (Dynamic BALMAT), was developed to calculate the layer moduli after converting dynamic deflections into static deflections. In situ tests were carried out to evaluate the applicability and reliability of the backcalculation procedure, which can accommodate the dynamic effect. In situ tests included FWD tests at the site of a Multi-Depth Deflectometer (MDD) installation. From the test results, it was found that DYN-BAL gives the most reliable results when compared with several other computer codes in use.