Design and Load Testing of Large Diameter Open-Ended Driven Piles. National Cooperative Highway Research Program (NCHRP) Synthesis 478. A Synthesis of Highway Practice.

摘要

he design and load testing of driven pipe piles is strongly influenced by the diameter and thickness of the pile. Common design methods to determine the load carrying capacity of a large diameter open-end cylinder pile are based on solid and small diameter pipe piles for skin friction and end bearing, respectively (McVay 2004). These design methods do not account for the differences in soil-pile-hammer interaction between small and large diameter driven piles. Issues include the degree of soil plugging or internal skin friction that exists, non-linear vibration effects and scalability concerns. Furthermore, significant questions have been raised regarding capacities determined by dynamic means, often requiring static tests to verify capacity (TRB 2004). A study of current practices for the design, testing, and use of large diameter driven pipe piles in highway applications is needed as transportation agencies begin to calibrate resistance factors for this type of deep foundation system. The project objectives are: (1) To locate and assemble documented information on the design, installation, and testing of large diameter cylinder piles; (2) To learn what practice has been used for estimating and verifying capacity of large diameter open end piles; (3) To identify all ongoing research; (4) To learn what problems remain largely unsolved; and (5) To organize, evaluate, and document the useful information that is acquired. Information will gathered through a literature review and a survey of State DOTs. Information Sources: ? Transportation Research Board, AFS30 Committee, Foundations of Bridges and Other Structures, Chair: Brian Liebich ? Deep Foundations Institute (DFI). ? Pile Driving Contractors Association (PDCA). ? Liebich, B. “High-Capacity Piles at the Stony Creek Bridge Project.” Transportation Research Record: Journal of the Transportation Research Board, Issue 2116, 2009, pp 41-46. ? Rausche, F., and Webster, S. 2007. “Behavior of Cylinder Piles during Pile Installation.” GSP 158 Contemporary Issues in Deep Foundations, American Society of Civil Engineers, Reston, VA. Dasenbrock, D. “Time Dependent Open-End Pipe Pile Capacity Assessment by Dynamic and Quasi-Static Methods.” Proceedings of the 31st Annual Conference on Deep Foundations, 2006, Washington, DC, USA, (DFI).