ABSTRACT
The widespread use of equations (1) and (2) in practice, prompted the study presented here into the factors affecting the values of βc (=1/αs) and αb for bored (non-displacement) piles in cohesionless soil. The paper initially provides an overview and discussion of factors affecting shaft and base capacity. Recent studies performed in the centrifuge on wished-in-place piles are then examined and are seen to yield important insights into the factors controlling shaft friction. These insights are employed to assist interpretation of the shaft friction measured in two instrumented augered piles at a sand site in Perth, Australia. A recently compiled database of augered piles, comprising 12 static load tests in Perth sand, is then presented and the interpreted base and shaft resistances are examined using the framework established for estimation of shaft friction and previously published numerical predictions for base capacity. Finally, some recommendations are provided to assist bored pile design in sand.
