Abstract
Portable falling weight deflectometer has been used to evaluate stiffness of subgrade and/or subbase. The stiffness is estimated using a pair of peak values of load and displacement. However, test data are dependent on specification of measurement apparatus. Instead of peak values of load and displacement, this study have used historical time data of load and displacement to estimate layer stiffness. The estimated stiffness was comparable to the one obtained from plate bearing tests. The objectives of the study are to improve accuracy on estimated stiffness and to decrease influence of individual apparatus specification.
