|Project Name:||Improved Reliability Modeling and Analysis for Primary Pavement Distress Models of Mechanistic-Empirical Design Guide|
Office of Infrastructure Research and Development |
|Team:||Pavement Design and Construction Team|
Infrastructure Research and Technology Strategic Plan and Roadmap|
|Project Description:||This study is concerned with enhancing the reliability analysis currently used in the Mechanistic-Empirical Pavement Design Guide. The Mechanistic-Empirical Pavement Design Guide uses a set of mechanistic-empirical models to analyze distresses of pavement structures in response to traffic, climate, and materials. These models include transverse joint faulting and transverse cracking for rigid pavements, and permanent deformation, fatigue cracking, and thermal cracking for flexible pavements. In order to evaluate the reliability of a selected pavement structure, the current procedure utilizes the overall standard deviation of the measured distresses obtained from calibration against distressed pavements in comparison with predicted values. This technique is fairly simple; however, it is far from accurate. Some limitations of the method may be attributed to the standard deviation being calibration-site specific, as well as the assumption of normality of the distribution of the measured distress levels. Additionally, this method relies on the variability of the measured output rather than on the variability/uncertainty of the input parameters that induce such variability in distress. The identification of an improved methodology for assessing design reliability is a top priority. In this study, the uncertainties in model input parameters (materials, climate, traffic) due to inherent spatial variability of materials and testing nonuniformity will be incorporated by using a number of advanced reliability techniques to assess the reliability of flexible and rigid pavements. Both analytical and simulation will be investigated. Materials variability and uncertainty associated with estimating many other input parameters will be determined from historical records. The reliability associated with pavement smoothness, as a primary measure of ride quality, in response to the various distresses encountered will be analyzed. Design reliabilities obtained from the various methods used will be compared to the current method. Advantages and disadvantages of the new methodologies in comparison with the current method will be discussed in light of both the accuracy and computational feasibility or practicality.|
|Start Date:||August 19, 2007|
|End Date:||March 28, 2009|
The key project objectives are:
(1) Reliable and effective pavement design.
(2) Efficient reliability analysis for pavement design.
|Test Methodology:||Numerical Analysis|
Washington State University; Role(s): Technical|
|Expected Benefits:||The successful outcome will improve the reliability of Mechanistic-Empirical Pavement Design Guide predictions and address some of the shortcomings in the current approach.|
|Deliverables:||Name: Technical Papers|
Product Type(s): Other
Description: Two technical papers: Thyagarajan, S., Muhunthan, B., Sivaneswaran, N. and Petros, K. “Efficient Simulation Techniques for Reliability Analysis of Flexible Pavements Using the Mechanistic‐Empirical Pavement Design Guide”, accepted for publication in the Journal of Transportation Engineering, ASCE (published online on 12 March 2011). Thyagarajan, S., Sivaneswaran, N., Muhunthan, B. and Petros, K. “Statistical Analysis of Critical Input Parameters in Mechanistic Empirical Pavement Design Guide”, 85th Annual Meeting and Technical Sessions of the Association of Asphalt Paving Technologists, Sacramento, California, March 7-10, 2010.
|Project Findings:||The research findings have been presented in three peer-reviewed journal papers. The research developed an efficient reliability procedure applicable to the National Cooperative Highway Research Program 1-37A Mechanistic-Empirical Pavement Design Guide and statistical analysis procedures for the identification of critical project-specific input parameters.|
Types of Cracking