Expansive clay soils that are susceptible to shrink and swell, and silty soils that are susceptible to frost heave are found in many parts of the United States. At these locations, these soils serve as the subgrade of the pavement structure. The AASHTOWare Pavement ME Design (formerly DARWin-ME) and the AASHTO Mechanistic-Empirical Pavement Design Guide Manual of Practice (MEPDG) (see Special Note A) provide a methodology for the analysis and performance prediction of new and rehabilitated pavements. Although the performance of these pavements is known to be closely related to properties of the subgrade, the performance predicted by this methodology does not adequately consider the influence of subgrade soils susceptible to shrink/swell and/or frost heave on pavement performance. There is a need to evaluate the procedures contained in the Pavement ME Design and identify or develop enhancements (in the form of modified or new models) to ensure that the procedures appropriately account for the influence of these types of subgrade soils on the performance of new and rehabilitated pavements. Incorporating these enhancements into the Pavement ME Design procedures will allow an improved analysis and design of pavement structures.
The objective of this research is to propose enhancements, as needed, to the Pavement ME Design procedures to better reflect the influence of subgrade soils susceptible to shrink/swell and/or frost heave on pavement performance. These enhancements shall include modifications of the models contained in the Pavement ME Design and/or the development of new models. The research shall address all new and rehabilitated pavement types included in Pavement ME Design.
Accomplishment of the project objective will require at least the following tasks.
The NCHRP is seeking the insights of proposers on how best to achieve the research objective. Proposers are expected to describe research plans that can realistically be accomplished within the constraints of available funds and contract time. Proposals must present the proposers' current thinking in sufficient detail to demonstrate their understanding of the issues and the soundness of their approach to meeting the research objective. Task descriptions are intended to provide a framework for conducting the research.
Task 1. Collect and review information relevant to the influence of subgrade soils susceptible to shrink/swell and/or frost heave on pavement performance, and identify models for addressing such influence.
Task 2. Evaluate the adequacy of Pavement ME Design models to predict the influence of subgrade soils susceptible to shrink/swell and/or frost heave on the in-service pavement performance for a range of relevant factors (e.g., material, environment, and traffic conditions).
Note: For availability of the Pavement ME Design software, see Special Note A.
Task 3. Based on the findings of Task 2, propose an updated plan to be executed in Phase II to improve the predictive ability of Pavement ME Design by modifying the models contained in the Pavement ME Design and/or developing new models. The plan must address the evaluation of potential models with regard to their ability to predict performance, ease of implementation in Pavement ME Design, and other relevant considerations. The plan must also describe the approach for calibrating and validating the proposed models.
1. Proposers must include in the proposal a plan that provides detail on the proposer’s current thinking regarding the work anticipated in Phase II. The work proposed for Task 5 must be divided into subtasks, and proposers must describe in detail the work proposed in each subtask.
2. The updated plan for Phase II must provide a clear, specific description of the process proposed for further developing/validating the enhanced models, including information on the data elements required for validating each model (type, range, and quantity) and their availability (e.g., quantity, ranges, and sources), the process for evaluating the quality of available data and their suitability for use in this research, the plan for dealing with data shortage and acquiring the needed data (e.g., conducting laboratory or field tests, and suggesting estimates), and the ranges of applicability and limitations of the proposed models.
Task 4. Prepare an interim report that documents the research performed in Tasks 1 through 3. Following review of the interim report by the NCHRP, the research team will be required to make a presentation to the project panel. Work on Phase II of the project will not begin until the interim report is approved and the Phase II work plan is authorized by the NCHRP. The decision on proceeding with Phase II will be based on the contractor’s documented justification of the updated work plan.
Task 5. Execute the plan approved in Task 4, and propose enhancements (in the form of modified or new models) to Pavement ME Design to better reflect the influence of subgrade soils susceptible to shrink/swell and/or frost heave on pavement performance.
Note: Any software developed in this research must be alfa-tested and submitted together with appropriate documentation and user manuals.
Task 6. Identify issues affecting implementation of the proposed enhancements (e.g., need for new data elements, new test methods and equipment, and increased effort), and propose possible actions to address these issues.
Task 7. Prepare a final deliverable that documents the entire research effort. The proposed enhancements shall be prepared as a stand-alone deliverable suitable for consideration and adoption by AASHTO. All data used in the research (e.g., for evaluation of potential models and for calibrating and validating identified models) shall be provided, in an electronic format with schema, as an attachment to the final deliverable.
Note: Following receipt of the draft final deliverables, the remaining 3 months shall be for NCHRP review and comment and for research agency preparation of the final deliverables.
A. AASHTOWare Pavement ME Design and the Mechanistic-Empirical Pavement Design Guide: A Manual of Practice, Second Edition (Item Code MEPDG-2) are available from the American Association of State Highway and Transportation Officials (AASHTO), 444 N. Capitol Street, NW, Washington, DC 20001. The Pavement ME Design software will be provided to the selected contractor at no cost to the project. However, $2,000 should be allocated for charges in connection with installation and tech support.
B. A review meeting that includes a presentation by the research team to the project panel should be scheduled during Phase II.
C. Resumes of research team members must present relevant qualifications and be limited to no more than 2 pages for each member. The section on equipment and facilities (Item 8 in the proposal) shall describe relevant information and be limited to no more than 3 pages.
D. Proposals should include a task-by-task breakdown of labor hours for each staff member as shown in Figure 4 in the brochure, "Information and Instructions for Preparing Proposals" (http://onlinepubs.trb.org/onlinepubs/crp/docs/ProposalPrep.pdf). Proposals also should include a breakdown of all costs (e.g., wages, indirect costs, travel, materials, and total) for each task using Figures 5 and 6 in the brochure. Please note that TRB Cooperative Research Program subawards (selected proposers are considered subawards to the National Academy of Sciences, the parent organization of TRB) must comply with 2 CFR 200 – Uniform Administrative Requirements, Cost Principles, and Audit Requirements for Federal Awards. These requirements include a provision that proposers without a "federally" Negotiated Indirect Costs Rate Agreement (NICRA) shall be subject to a maximum allowable indirect rate of 10% of Modified Total Direct Costs. Modified Total Direct Costs include all salaries and wages, applicable fringe benefits, materials and supplies, services, travel, and up to the first $25,000 of each lower-tier subaward and subcontract. Modified Total Direct Costs exclude equipment, capital expenditures, charges for patient care, rental costs, tuition remission, scholarships and fellowships, participant support costs and the portion of each lower-tier subaward and subcontract in excess of $25,000.
E. The NCHRP is a practical, applied research program that produces implementable products addressing problems faced by transportation practitioners and managers. The benefits of NCHRP research are realized only when the results are implemented in state DOTs and other agencies. Implementation of the research product must be considered throughout the process, from problem statement development to research contract and beyond completion of the research. Item 4(c), "Anticipated Research Results," must include the following: (a) the "product" expected from the research, (b) the audience or "market" for this product, (c) a realistic assessment of impediments to successful implementation, and (d) the institutions and individuals who might take leadership in deploying the research product. The project panel will develop and maintain an implementation plan throughout the life of the project. The research team will be expected to provide input to an implementation team consisting of panel members, AASHTO committee members, the NCHRP Implementation Coordinator, and others in order to meet the goals of NCHRP Active Implementation: Moving Research into Practice, available at http://onlinepubs.trb.org/onlinepubs/nchrp/docs/NCHRP_ActiveImplementation.pdf.
F. Item 5 in the proposal, "Qualifications of the Research Team," must include a section labeled "Disclosure." Information relevant to the NCHRP's need to ensure objectivity and to be aware of possible sources of significant financial or organizational conflict of interest in conducting the research must be presented in this section of the proposal. For example, under certain conditions, ownership of the proposing agency, other organizational relationships, or proprietary rights and interests could be perceived as jeopardizing an objective approach to the research effort, and proposers are asked to disclose any such circumstances and to explain how they will be accounted for in this study. If there are no issues related to objectivity, this should be stated.
G. Proposals are evaluated by the NCHRP staff and project panels consisting of individuals collectively very knowledgeable in the problem area. Selection of an agency is made by the project panel considering the following factors: (1) the proposer's demonstrated understanding of the problem; (2) the merit of the proposed research approach and experiment design; (3) the experience, qualifications, and objectivity of the research team in the same or closely related problem area; (4) the plan for ensuring application of results; (5) the proposer's plan for participation by Disadvantaged Business Enterprises--small firms owned and controlled by minorities or women; and (6) the adequacy of the facilities.
Note: The proposer's plan for participation by Disadvantaged Business Enterprises should be incorporated in Item 12 of the proposal.
H. Copyrights - All data, written materials, computer software, graphic and photographic images, and other information prepared under the contract and the copyrights therein shall be owned by the National Academies of Sciences, Engineering, and Medicine. The contractor and subcontractors will be able to publish this material for non-commercial purposes, for internal use, or to further academic research or studies with permission from TRB Cooperative Research Programs. The contractor and subcontractors will not be allowed to sell the project material without prior approval by the National Academies of Sciences, Engineering, and Medicine. By signing a contract with the National Academy of Sciences, contractors accept legal responsibility for any copyright infringement that may exist in work done for TRB. Contractors are therefore responsible for obtaining all necessary permissions for use of copyrighted material in TRB's Cooperative Research Programs publications. For guidance on TRB's policies on using copyrighted material please consult Section 5.4, "Use of Copyrighted Material," in the Procedural Manual for Contractors.