Continuous Flight Auger (CFA) piles

what are cfa piles?

Continuous Flight Auger piles, also known as Auger Cast Piles, are a type of cast-in-place deep foundation used to transfer building loads through weak or unsuitable near-surface soils into deeper, more competent soil or bearing layers.

CFA piles are installed by drilling a continuous, hollow stem auger into the ground to the required depth. Once design tip elevation is reached, concrete is pumped through the hollow stem of the auger into the borehole as the auger is slowly retrieved. Once the auger is removed from the ground and the borehole is filled with concrete, steel reinforcing is placed into the fresh concrete, creating a reinforced concrete pile into the ground. The steel reinforcing can consist of a circular cage, one center bar, or both. These economical piles range in diameter from 14- to greater than 36-in with depths extending up to approximately 200-ft.

what are the advantages of cfa piles?

Because drilling and concrete placement occur as part of one continuous process, CFA piles can often be installed efficiently, making them well suited for projects with demanding construction schedules. CFA piles are installed using a rotary drilling process rather than driving piles into the ground. This significantly reduces vibration, making them a strong option for projects adjacent to existing buildings and other sensitive structures. The drilling process generally produces less noise than driven pile systems, which can be beneficial on projects in dense urban environments. CFA piles can be used across a wide range of soil conditions and can be designed to develop capacity through both friction and end bearing, depending on the project’s geotechnical requirements.