ACI 336

Drilled Shaft Construction: The Cast-in-Place Deep Foundation for High-Capacity Loads

Drilled shafts (also called caissons or bored piles) are large-diameter cast-in-place concrete deep foundations. Drilling rigs excavate holes; reinforcement and concrete fill them. Capacities exceed driven piles. Bridge foundations, large buildings, and specialty applications use drilled shafts. Understanding construction helps contractors coordinate this specialty deep foundation.