Development of Alabama Traffic Factors for Use in Mechanistic-Empirical Pavement Design.

摘要

The pavement engineering community is moving toward design practices that use mechanistic-empirical (M-E) approaches to the design and analysis of pavement structures. This effort is embodied in the Mechanistic-Empirical Pavement Design Guide (MEPDG) that was developed over the last several years through the National Cooperative Highway Research Program (NCHRP) and accompanying AASHTOW are Pavement ME Design? software. As ALDOT moves toward implementation of M-E pavement design, the need to evaluate the effects of differences among the many types of traffic data on pavement design became apparent. This research project examined the differences among national-level traffic inputs developed through the aforementioned NCHRP studies (and now included as the default traffic data in the Pavement ME Design? software), state-level traffic inputs developed from data collected at ALDOT’s weigh-in-motion (WIM) sites, and site-specific data. The full range of traffic inputs considered in the M-E design process was divided into 13 groups; the effects of the three levels of data were evaluated separately for each group. A rational, unbiased, quality control procedure for ALDOT WIM data was developed and applied to the data. Traffic inputs at levels 1 (national), 2 (state or regional), and 3 (site-specific), as specified in the design software, were then developed. The sensitivity of the pavement thickness required to not exceed a specified set of allowable pavement distresses, for both flexible and rigid pavements, to different levels of traffic data in Alabama was then determined. Finally, axle load spectra recommendations for flexible and rigid pavement design were made for future use by ALDOT.