Mechanistic-empirical Pavement Design Guide Implementation

Final report.PDFTech ReportFHWA-SC-10-01GT06-10Pavement designEmpirical methodsMechanistic designImplementationSouth CarolinaUniversity of South Carolina. Dept. of Civil & Environmental EngineeringBaus, R. L.Stires, N. R.University of South Carolina. Dept. of Civil & Environmental EngineeringSouth Carolina. Dept. of TransportationUnited States. Federal Highway AdministrationNTL-HIGHWAY/ROAD TRANSPORTATION-DesignUS Transportation CollectionThe recently introduced Mechanistic-Empirical Pavement Design Guide (MEPDG) and associated computer software provides a state-of-practice mechanistic-empirical highway pavement design methodology. The MEPDG methodology is based on pavement responses computed using detailed traffic loading, material properties, and environmental data. The responses are used to predict incremental damage over time. Design is an iterative process using analysis results based on trial designs postulated by the designer. A trial design is analyzed for adequacy against user input performance criteria. These criteria are established by policy decisions and represent the amount of distress or roughness that would trigger some major rehabilitation or reconstruction activity. The output of the computer software is a prediction of distresses and smoothness against set reliability values. If the predictions do not meet the desired performance criteria at the given reliability, the trial design is revised and the evaluation is repeated. The MEPDG method provides for three hierarchical levels of design inputs to allow the designer to match the quality and level of detail of the design inputs to the level of importance of the project (or to best utilize available input data). In addition to inputs required to quantify a trial pavement structure, the MEPDG requires over 100 inputs to characterize traffic loading, material properties, and environmental factors.Currently, the South Carolina Department of Transportation (SCDOT) designs flexible and rigid pavement structures using AASHTO regression equation methodology (1972 and later with some modifications). Implementation of the MEPDG will require a substantial effort. This report summarizes an initial study undertaken to 1) gain an understanding of the new methodology, required inputs, and limitations, 2) conduct preliminary input sensitivity studies and review sensitivity studies performed by others, and 3) summarize implementation strategies undertaken or planned at other state highway agencies. Based on this investigation, general recommendations for SCDOT MEPDG implementation are proposed