Framework for Reliability Analysis of Pavement Structures using the Mechanistic-Empirical Pavement Design Guide

摘要

We propose a framework for estimating the reliability of a given pavement structure as analyzedby the Mechanistic-Empirical Pavement Design Guide (MEPDG). The methodology uses apreviously developed response surface fit, in place of time-demanding implicit limit statefunctions used within the MEPDG, in combination with an analytical approach to estimatingreliability using First-Order and Second-Order Reliability Methods (FORM and SORM).Additionally, in order to assess the accuracy of the FORM and SORM reliability estimates,Monte Carlo simulations are also performed.A case study is used to demonstrate the methodology. A three-layered pavement structureis selected consisting of HMA (hot-mix asphalt), base, and subgrade. Several pavement designvariables are treated as random; these include HMA and base layer thicknesses, base andsubgrade modulus, and HMA layer binder and air void content. Information on the uncertainty ofand correlation between these variables is obtained from the Long-Term Pavement Performance(LTPP) program.Several response surfaces for limit states dealing with HMA rutting failure are fit usingmany runs of the MEPDG based on a factorial design of combinations among theaforementioned random variables, as well as on traffic and climatic considerations. Theseresponse surfaces are then used to analyze the reliability of the given pavement structure. It isfound that MEPDG reliability estimates are conservative and it is verified that the use ofFORM/SORM or simulation based on response surfaces is an accurate method to estimate thereliability of pavement structures.