Caissons

Caissons, or drilled shafts, are typically high-capacity cast-in-place deep foundation elements constructed using an auger. A hole having the design diameter of the planned shaft is first drilled to the design depth. If the hole requires assistance to remain open casing or drilling fluid is used. Full-length reinforcing steel is then lowered into the hole and the hole is filled with concrete. The finished foundation element resists compression, uplift, and lateral loads. The technique has been used to support buildings, tanks, towers, and bridges.