Determination of Layer Moduli from Falling Weight Deflectometer Measurements

摘要

Backcalculation programs are used for evaluation of pavement layer moduli fromfalling weight deflectometer (FWD) measurements. In the study, a comparison of two programs with different calculation methods. Modulus and Elmod, is made using deflection data derived from 43 SHRP-LTPP (Strategic Highway Research Program, Long-Term Pavement Performance) test sections. Critical strains were calculated using the linear program (BISAR) with layer moduli from the Modulus-program as input and with the Elmod-program. It was found, that calculated strains from the two programs agree very well, even though the calculated moduli are quite different. Calculated strains from FWD loading were compared with measured strains under moving wheel load from the fiel at Virttaa test site. The differences between the two are most likely due to differences in the loading conditions and in the method of analysis.