Superiority of dynamic backcalculation of FWD time series data

A falling weight deflectometer (FWD) is widely used to make pavement structural evaluation. It is dynamic testing equipment which applies impulse force at a surface of pavement and measures surface deflections. However, only peak load and peak surface deflections are commonly recorded. And by regarding them as pseudo-static load and deflections, static backcalculation is employed to estimate layer moduli. Static backcalculation disregards rich information that time series data may possess. This paper presents backcalculated results of all layers from time series data. Also it demonstrates that dynamic backcalculation can estimate the modulus and damping coefficient of all layers from even a set of load and deflection time histories at one location.