Introduction

A drilled shaft is a deep foundation that is constructed by placing concrete in an excavated hole. Reinforcing steel can be installed in the excavation, if desired, prior to placing the concrete. A schematic example of a typical drilled shaft socketed into rock is shown in Figure 1.1. The drilled shaft can carry both axial and lateral loads. Drilled shafts are sometimes called bored piles, piers, drilled piers, caissons, drilled caissons, or cast-inplace piles.