Assessing Driven Steel Pile Capacity on Rock Using Empirical Approaches

Abstract

Methods of determining pile toe capacity for both small displacement driven steel piles and drilled sockets were collected. Working in conjunction with a local consulting firm, records of previous pile driving sites were collected. A process to determine quality data for use in this work was developed by the author including information from geotechnical site investigations, pile driving records and pile driving analysis records. By plotting unconfined compressive strength of rock versus measured ultimate pile toe capacity of these piles, a best fit line of 7.5qu and a series of confidence intervals were established for the site records. This best fit line was compared to all of the previously reviews design methods for calculating ultimate pile toe capacity. Rehnman and Broms (1971) was determined to be the most effective existing method while most of the methods for drilled sockets were overly conservative when applied to small displacement driven steel piles.