Knowledge-based design and construction of driven piles

Abstract

Specified numbers of static load tests (e.g., 1% of working piles) and dynamic tests (e.g., 10% of working piles) are often required in Hong Kong to verify the reliability of driven piles for every single project. In this research, a pile database, the Hong Kong Driven Pile Database, is developed: (a) to systematically compile historic driven pile data, which include pile data, soil investigation data, static load test results, dynamic test results and case pile wave analysis program results; (b) to provide data for reliability evaluation of design methods; (c) to assist in design of future foundation projects based on past experience; and (d) to learn from past failures. The database contains information on 1514 piles, including 308 static load test piles. In this paper, the basic information of the database such as the sources of piling data and the major components of the database is first described. Then the reliability of five termination criteria for piledriving control is evaluated against the pile test information in the database. Subsequently, a performance evaluation of three driving-stress analysis methods is conducted based on information in the database. Finally, to demonstrate possible knowledge-based pile design and construction using the database, a design example is presented illustrating how the database can be used to assist in the early stage of pile design for a future project. The information on hammers, range of final set values and resulting pile performance in case histories of similar projects can be used as a reference for the engineer to expedite design for new projects. The engineer can also learn from the past pile failures contained in the database.