A Practical Approach to Incorporate Roughness-Induced Dynamic Loads in Pavement Design and Performance Prediction

TLDR: In this paper, the effects of both pavement roughness and vehicle speed on the dynamic loads developed at the tire pavement interface are evaluated along with their effects on the performance of pavement structures.

Abstract: Traffic constitutes a fundamental parameter in the analysis, design and performance prediction of pavement structures. Although the current mechanistic empirical pavement design guide uses axle load spectra to characterize the traffic variable for pavement design purposes, pavements around the world continue to be designed using the equivalency single axle load concept, which is based on the static load of the vehicles (dead weight). However, the dynamic loads induced by roughness can be considerably higher than the static load in specific locations of a pavement section, causing an unexpected adverse impact on the performance of pavement structures. In the present investigation, the effects of both pavement roughness and vehicle speed on the dynamic loads developed at the tire pavement interface are evaluated along with their effects on the performance of pavement structures. In order to achieve the above objective, 787 pavement profiles were analyzed, combining rural and urban environments, as well as rigid and flexible pavement sections. The dynamic load produced at the tire pavement interface for all pavement profiles was modeled. Two roughness indices, The International Roughness Index (IRI) and the Dynamic Load Index (DLI), were determined for each profile. A correlation model between the IRI and the DLI was developed. Additionally, a Traffic Correction Factor (TCF) was proposed to account for the dynamic load effects induced by roughness and vehicle speed. The proposed TCF could be used to modify the estimation of traffic damage on road sections with high roughness levels, therefore improving future performance prediction processes. Finally, a methodology to calculate the reduction of the remaining life of a pavement structure due to the surface roughness was proposed.