Auger-cast Piles

Auger-cast piles, also known as continuous flight auger piles (CFA), are deep foundation elements that are cast-in-place using a hollow stem auger with continuous flights. The auger is drilled into the soil and/or rock to design depth. The auger is then slowly extracted, removing the drilled soil/rock as concrete or grout is pumped through the hollow stem. The grout pressure and volume must be carefully controlled to construct a continuous pile without defects. Reinforcing steel is then lowered into the wet concrete or grout. The finished foundation element resists compression, uplift and lateral loads. The technique has been used to support buildings, tanks, towers, and bridges.