The AASHTO Guide for the Design of Pavement Structures (Guide) is the primary document used to design new and rehabilitated highway pavements. Throughout the highway community, the major pavement-design emphasis is now on rehabilitation, for which empirical design approaches often are inadequate. Because mechanistic approaches more realistically characterize in-service pavements and improve the reliability of designs, it is expected that the next generation of design approaches will rely heavily on mechanistic principles. However, because of the gaps that exist in the knowledge base, mechanistic design methods will need to be supported by empirical relationships, and many of the issues relating to the mechanistic-empirical approach need to be better defined before practical and realistic design procedures can be developed and put into use.

The AASHTO Joint Task Force on Pavements (JTFP) is responsible for the development and implementation of pavement design technologies. This charge has been pursued by the Task Force since the AASHO Road Test and recently led to the development of the 1993 Guide. More recently, the JTFP initiated an effort to develop an improved Guide by the year 2002 (2002 Guide). As part of this effort, a workshop was convened on March 24-26, 1996, in Irvine, California, to develop a framework for improving the Guide. The workshop attendees--pavement experts from public and private agencies, industry, and academia--addressed the areas of traffic loadings, foundations, materials characterization, pavement performance, and environment to help determine the technology best suited for inclusion in the 2002 Guide.

NCHRP Project 1-37 will initiate the process of developing the 2002 Guide. Information that will be incorporated into the Guide and the topics that need adjustments will be identified, and appropriate language for use in the Guide will be developed. Improvements that require a major research effort will not be appropriate for the 2002 Guide.

The 2002 Guide will be developed under the oversight of NCHRP Project Panel C1-37, but it will be important to ensure coordination, during the project, with the JTFP--the AASHTO group responsible for the Guide. It is also essential to coordinate efforts with researchers, industry, and organizations producing material relevant to the 2002 Guide. A contractor is needed to bring together the existing and new knowledge into a single, cohesive document.

The objectives of this project are to (1) develop and deliver a document and associated software for adoption and distribution by AASHTO as the 2002 AASHTO Guide for Design of New and Rehabilitated Pavement Structures, (2) work with responsible parties to facilitate AASHTO approval and user implementation, and (3) develop a plan to support use of the guide. The 2002 Guide shall, to the largest extent possible, be based on sound mechanistic principles. Accomplishment of these objectives will require coordinating with AASHTO member departments and committees, FHWA, TRB, industry representatives, and other groups to provide input and review technical material developed during the course of the project, to facilitate use of results of other research efforts, and to provide other pertinent information to aid with the preparation of the draft and final versions of the Guide.

The following tasks are anticipated: (1) Review the current AASHTO Guide for Design of Pavement Structures and recommend changes in format, content, presentation, and other matters that should be considered in the development of the 2002 Guide. Prepare and submit for NCHRP review and approval a strategic plan for developing the 2002 Guide. The plan, to be submitted not later than 30 days from contract award, shall identify proposed research team members and their qualifications, outline the project schedule, delineate milestones, detail required resources, describe implementation and marketing strategies, and address users' involvement. Following review of the plan by the NCHRP, the project manager will be required to make a presentation to the project panel. Panel comments shall be addressed in a revised version of the plan. (2) Collect and review relevant domestic and foreign literature and research findings, and monitor ongoing research activities to obtain the information needed to develop the 2002 Guide. Identify those critical issues that must be resolved to develop and implement a mechanistic-empirical approach to pavement design and rehabilitation. (3) Develop and submit for NCHRP approval, an action plan to address issues identified in Tasks 1 and 2. The plan shall present an approach for developing and incorporating models in the design procedure; evaluating and validating--with consideration to accuracy, reliability, ease of use, and other relevant criteria--the suitability of the procedures; and addressing other relevant issues. (4) Develop and submit for NCHRP approval, a plan for implementation, training, and related activities. The plan must ensure coordination with AASHTO, AASHTO member departments, the FHWA, industry representatives, and other groups to facilitate review of draft versions of the Guide, adoption of the Guide by AASHTO, and use of the Guide by the various highway agencies. (5) Execute the action plan and framework approved in Tasks 3 and 4, respectively. (6) Write, produce, and deliver, by July 1, 1999, an initial draft of the proposed 2002 Guide and related software, for review by the NCHRP. (7) Following review of the initial draft, produce and deliver a second draft of the proposed 2002 Guide and associated software by March 1, 2000, for review by the JTFP and other involved parties. (8) Following review of the second draft, produce and deliver a final draft of the proposed 2002 Guide by September 1, 2000. (9) Submit a preliminary draft final report that documents the entire research effort. The report shall identify future research needs that would provide further enhancement to the 2002 Guide. The proposed 2002 Guide shall be prepared as a stand-alone document, in a format suitable for consideration and adoption by AASHTO. (10) Submit a draft final report that incorporates the reviewers' comments.

Status: Project 1-37 was the initial step in the process of developing the 2002 Guide; a draft work plan for developing the Guide was submitted for review by the NCHRP. A decision has been made not to pursue further work under Project 1-37. Further work to develop the 2002 Guide will be performed under Project 1-37A.

Report Availability: No reports are available.