Cone penetration test (CPT) methods for end-bearing assessment of open- and closed-ended driven piles in siliceous sand

The cone penetration test (CPT) has been used as a means of assessing the end bearing of driven piles in sand for many decades. This paper examines the predictive performance of four new such CPT-based methods recently included in the commentary of the 22nd edition of the American Petroleum Institute’s recommended practice for fixed offshore structures. It is demonstrated that the formulations given by one of these methods, referred to as UWA-05, provides better predictions than the three other CPT methods when tested against (i) an existing database of base-capacity measurements, (ii) results from a new series of load tests on small-diameter piles, and (iii) base capacities measured in two recently conducted load tests on 1.5 m diameter pipe piles. It is shown that the UWA-05 has better predictive performance (and hence reliability) as it accounts explicitly for the effects of partial plugging during pipe–pile installation and for variations in CPT resistance in the vicinity of the pile tip.