A Study on the Evaluation of Layer Properties of Flexible Pavement with Respect to Dynamic Effects of Falling Weight Deflectometer I : Development Backanalysis Procedure

Most backcalculation programs used to evaluate pavement layer properties assume dynamic deflections as static deflections. This research aims to take into consideration the dynamic effects of the deflection basin from the Falling Weight Deflectometer(FWD) in the backcalculation procedure. Dynamic effects of FWD data were studied analytically and pseudo-static deflection factors were proposed. Pseudo-static deflection factors were derived from the regression analyses between the static and dynamic calculated deflection basins for three-layer systems with asphalt stabilized babe in asphalt concrete pavement. Bedrock thicknesses of 2m, 4m, 6m, and 20m were considered for analyses, Based on the results from the regression analyses, average relative error was found to be 2.2% between the psuedo-static deflections converted from dynamic deflections and static deflections. The algorithm in Backanalysis of Asphalt Layer Modulus and Thickness was modified to reflect the dynamic effects in the backcalculation process. A modified backcalculation procedure, DYN-BAL, was developed using the pseudo-static deflection factors. For the verification of a modified backcalculation procedure, DYN-BAL, numerical model tests were carried out. This paper (Part I) presents the pseudo-static backcalculation procedure, and a companion paper (Part II) presents the reliability of this approach in which the backcalculation procedure was verified using field and lab tests.