Sampling-Based Flexible Pavement Design Reliability Evaluation of NCHRP Mechanistic-Empirical Pavement Design Guide

The Mechanistic-Empirical Pavement Design Guide (MEPDG) Version 0.9 developed under NCHRP 1-40 is a very complex tool for the evaluation of pavement structures. The predictions of distress which are provided by the software are considered to be a mean (50% reliability) result based on the input parameters utilized. In addition, it allows the designer the option to select other design reliability levels based on the need of the design project. It is assumed that this reliability would account for all the variation in the design inputs and model parameters. This research provides a method to evaluate the variation of the predicted outputs based on the assumed variability of the selected input parameters. The study varied the following input parameters, AADTT, HMA surface mix properties, HMA base mix properties, HMA base and crushed stone thickness and moduli. A total of 100 design scenarios were randomly sampled from these inputs. Statistical techniques were utilized to illustrate that the variability of the predicted performance is not necessarily normally distributed. In general the areas which did not match the normal characteristics were primarily in the lower tails of the distributions. This has the potential to be significant, since many of our high type facilities are generally designed with high reliability but with lower distress levels. An alternative method for addressing reliability in MEPDG may be to look at the actual distribution of errors associated with predicted performance in conjunction with the variability associated with normal variation in design inputs.

Language

  • English

Media Info

  • Media Type: CD-ROM
  • Features: Figures; References; Tables;
  • Pagination: 19p
  • Monograph Title: TRB 86th Annual Meeting Compendium of Papers CD-ROM

Subject/Index Terms

Filing Info

  • Accession Number: 01043835
  • Record Type: Publication
  • Report/Paper Numbers: 07-3155
  • Files: TRIS, TRB
  • Created Date: Feb 8 2007 7:51PM