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3 Research Approach The approach used to develop the Recommended Practice and meet the objectives of NCHRP Project 10-86 was to be completed in four phases of work, as directed by the NCHRP Project 10-86 panel. These phases are described as follows: â¢ Phase 1âDevelop the Recommended Practice outline using a literature review, DOT Survey, and identification of gaps in knowledge in current practice. â¢ Phase 2âDevelop the Recommended Practice and prepare a working draft of the procedure. â¢ Phase 3âEvaluate and revise the Recommended Practice through a pilot project phase, testing the procedure on actual DOT drainage system projects. â¢ Phase 4âDevelop final deliverables including the Recom- mended Practice. This research approach was originally outlined in the work plan provided to the NCHRP Project 10-86 panel at the initiation of this project. However, as development of the Recommended Practice progressed, the details of the meth- odologies and approaches used in each phase of work were modified based on findings from the current state of practice and other lessons learned. Additional details of each of these phases, including findings and results, are described in this report. 2.1 Phase 1âDevelop the Recommended Practice Outline The first phase of the project involved the development of an outline of the Recommended Practice, including the key features that were necessary based on the current state of practice. That outline and the current state of practice were developed based on three critical tasks: a literature review, a survey of state DOTs, and the identification of gaps in knowledge. 2.1.1 Literature Review A literature review was performed to research and document current practices and was used to develop a working outline and a basic framework for the Recommended Practice, as well as to identify gaps in knowledge that may affect the Recom- mended Practice. The results of the literature review and the gaps in knowledge identified were used extensively to develop the draft Recommended Practice that was prepared in Phase 2 of this project. The literature review focused on the following topics: â¢ Existing bid practices â¢ Design and construction considerations (focusing on hydraulic and structural design) â¢ Long term performance and service life of pipe (durability) â¢ Post-installation inspection and acceptance criteria A reference database was developed to track each document reviewed, the reference type, and technical topics covered. A unique code was provided for each reference to track and organize the files. References from AASHTO, state DOTs, trade associations, regulatory and guidance agencies, federal agencies, and journals were included in the review. 2.1.2 Survey of State DOTs To complement the literature review, a survey of state DOTs was implemented to gather additional information on design, specification, bidding, installation oversight, inspection, and maintenance of drainage pipe systems to identify the current state of practice. The DOT survey was developed during the early stages of the project and after review and approval by the NCHRP Project 10-86 panel; it was sent to all the state DOTs through the members of the AASHTO Subcommittee on Materials. C H A P T E R 2
4The DOT survey and results are described in greater detail in Chapter 3. Based on the survey results, a long-list of potential states for participation in the pilot projects was identified. 2.1.3 Identification of Gaps in Knowledge and Practice Gaps in existing knowledge that affected the development of the Recommended Practice were identified in this phase of work. The techniques used to identify these critical gaps included consideration of previous NCHRP studies, the results of the literature review, the results of the DOT survey, and discussion with other agencies and technical resources. Gaps in practice were typically defined as either knowl- edge gaps or implementation gaps. Knowledge gaps are areas where there is a deficiency in design theory/methodologies or performance data to support rigorous and robust design and performance decisions. Implementation gaps occur where there is clear and technically valid information (design method, performance data, etc.) to support use of a design method, evaluation criteria, or pipe product, but implementation has not yet been instituted. 2.1.4 Recommended Practice Outline Based on results from the literature review, the DOT survey, and the identification of gaps in knowledge, an outline of the Draft Recommended Practice was prepared for the Phase 1 report, submitted in December 2011. The Draft Recommended Practice was further refined using the results of internal testing. The research team applied current state protocols to the Draft Recommended Practice to identify refinements and decision points. The Draft Recommended Practice was found to be applicable to the range of state policies and provided valu- able insight into some of the finer details necessary to more fully develop the Recommended Practice through the pilot project phase. 2.2 Phase 2âDevelop the Recommended Practice Testing the Recommended Practice through actual DOT pilot projects was essential to develop a final, implementable pro- cedure. This phase of work focused on developing a work plan for the pilot project phase as well as identifying appropriate projects to be used to test the procedure and evaluate the results within the required timeframe. After much coordination and contact with DOTs, projects were identified with Pennsylvania Department of Transporta- tion (PennDOT) and Missouri Department of Transportation (MoDOT). Additionally, the research team met with Florida Department of Transportation (FDOT) to discuss the Rec- ommended Practice and obtain feedback based on FDOTâs experience with alternative bidding of drainage systems. However, due to constraints experienced by most agencies in making an active project available for use as a full pilot project within the timeframe of NCHRP Project 10-86, a modified supplemental approach to this phase was used, consisting of the completion of seven additional baseline pilot projects. Application of each of these pilot projects is discussed in additional detail in Section 2.3. 2.3 Phase 3âEvaluate and Revise the Recommended Practice This phase of the research project consisted of evaluating the Recommended Practice through the pilot project phase, revising the Recommended Practice as needed, and developing an implementation plan so that the Recommended Practice could gain acceptance by AASHTO, state and local transpor- tation agencies, and industry. 2.3.1 Pilot Project Testing The purpose of the pilot project phase of NCHRP Proj- ect 10-86 was to assist in trialing and refining the Recom- mended Practice by applying a range of drainage scenarios, environmental conditions, technical evaluation criteria, and bidding policies. This phase was a key element to gaining acceptance of the recommendations and guidelines. It served to prove the feasibility of implementing the developed pro- cedures and to engage stakeholders (DOTs) in the development and refinement phases of the work. The pilot project phase also provided the opportunity to test implementation of the Recommended Practice on a small scale (on individual projects) with a few select DOTs providing insight into the requirements that will be needed to implement a new alternative bidding protocol into a state agency. Applying the Recommended Practice to the DOT pilot projects had two phases. Phase 1 consisted of applying the Recommended Practice per the agencyâs standard design methodologies. Phase 2 consisted of repeating the process using national standards, technical approaches, and protocols as recommended by the research team. The two pilot projects were performed at PennDOT and MoDOT. The baseline pilot projects consisted of the application of each agencyâs current policies to a common reference âbaselineâ project (for which the MoDOT pilot project was selected for comparison).
5 The baseline projects allowed for trialing and applying the Draft Recommended Practice across a wide range of agency policies developed under varying drainage, climatological, and environmental conditions; technical evaluation criteria; and bidding practices. This approach compared the Draft Recommended Practice with existing agency practices as applied to a standard project and identified where short- comings or complications could arise. The process allowed an evaluation of an agencyâs current protocols (design guide- lines, regulations, restrictions, etc.) with regard to alternative bidding and technical evaluation, and was intended to allow for early identification and handling of potential barriers to the adoption of the Recommended Practice by state DOTs. The baseline pilot projects were implemented with the cooperation of the specific agency so that the team could solicit feedback upon completion. 2.3.2 Revision of Recommended Practice and Implementation Plan This pilot project phase provided lessons learned that were used to improve the Recommended Practice. These lessons were also used to develop the implementation plan, so that the Recommended Practice could gain acceptance by AASHTO, state and local transportation agencies, and industry. 2.4 Phase 4âDevelop Final Deliverables including the Recommended Practice The final phase of the project focused on preparing the final Recommended Practice in AASHTO format and this report.