Specifications include, but are not limited to: Task 1. Conduct a literature review of relevant domestic and international research considered to be the state-of-the-practice on design of piles for downdrag. The domestic review shall include research conducted through the NCHRP; FHWA; and other national, state, and pooled-fund sponsored research. Task 2. Synthesize the literature review to identify the knowledge gaps and summarize information on the effectiveness of existing design methods of piles for downdrag. These gaps should be addressed in the final product or in the recommended future research as budget permits. Discuss the quantity and quality of data required to achieve the project objectives. Task 3. Propose methodology including field testing and numerical analyses, to be executed in Phase II, based on currently available data. At a minimum, the methodology shall consider the following items: ·Data requirements and collections methods; ·When and how to apply the neutral plane method, including limitations; ·Different soil types and subsurface conditions; ·Friction and end bearing piles; ·Static and seismic conditions including liquefaction; ·Different limit states; ·Different pile types and sizes; ·Pile group; and ·Mitigation techniques for downdrag.
