Proposed Loading Waveforms and Loading Time Equations for Mechanistic-Empirical Pavement Design and Analysis

Abstract

Under the same applied traffic loading, time is traditionally assumed to be a function of only the vehicle speed and the depth beneath the pavement surface. Additionally, no definite loading waveform has been established and/or recommended for any one special loading situation. After numerous computations and analyses in this study, it was found that the loading time is not only a function of the vehicle speed and the depth beneath the pavement surface but is also a function of the moduli ratio between the layer of interest and the immediate succeeding layer below. Furthermore, the loading waveform changed with depth beneath the pavement surface and the moduli ratio. Based on the results of this study, new equations for more accurately determining the loading time were proposed. Additionally, the corresponding loading waveform, which is a function of the depth beneath the pavement surface and the moduli ratio, was recommended. Plausible results were also obtained when an iterated method was introduced to calculate the loading time using the equations proposed in this paper.