Engineers Australia

Case study: Assessment of the shaft capacity of a driven pile in sand using CPT based methods

R. B. Kelly and P.K. Wong

Abstract

A number of CPT-based pile capacity prediction methods have recently been presented that claim to take friction fatigue into account. These methods were used to assess the shaft capacity of a 1.54m diameter steel tubular pile, driven to 40m depth, which showed substantial friction fatigue during driving. All of the methods over-predicted the shaft capacity at the end of drive. After a 34 day period to allow the pile to set-up, the NGI and UWA methods were found to most closely predict the shaft capacity inferred from a dynamic restrike test. The ICP method also produced similar results when an exponent of -0.5 for driven piles was used on the h/D ratio instead of -0.38.