Continuous Flight Auger (CFA) Piles

Continuous Flight Auger (CFA) piles are a type of drilled, or bored, foundation, made using the helical screw of a continuous flight auger, which acts a little like a drill bit on your standard hand-held electric drill. They’re a common, cost-effective, and fast means of pile construction.

Continuous Flight Auger

What Are CFA Piles Used For?

CFA piles are typically used to construct a foundational base that is ideal for use where various load cases are applied to the pile, from uplift and tension to lateral load. CFA piles are an effective solution for supporting significant lateral loads, with an allowable bearing capacity of up to 3,500 kN (depending on pile diameter and ground conditions). CFA piles are generally used as a foundation or support structure for:

CFA piling has become popular because of the continuous flight auger’s impressive instrumentation control, its depth and torque capabilities, and its minimal deformation of the adjacent ground or soil mass. It is also ideal for use on noise- and vibration-sensitive sites, such as built-up urban areas or in industrial contexts, because of its low levels of vibration and noise generation.

CFA Piling » cfa piling
CFA Piling » cfa piling
CFA Piling » cfa piling
Continuous Flight Auger

Ground Suitability

CFA piling was initially developed to enable the successful construction of piles in ground conditions with non-cohesive, granular, stratified and water-bearing soils, or with a weak soil structure below the groundwater table. However, CFA piling is now a commonly-used foundation in all manner of ground conditions due to its versatility, cost-effectiveness, and minimal need for site preparation.

CFA piling is not well-suited to use on projects that require very deep foundations, or where the pile needs to be drilled into very hard rock.

Continuous Flight Auger

How Are CFA Piles Constructed?

CFA piles are a type of drilled foundation, made using the helical screw of a continuous flight auger, which acts a little like a drill bit on your standard hand-held electric drill. The stem of the ‘drill bit’ (auger) has a hollow shaft, which is sealed while the auger arm is used to bore the shaft to the required depth.

Once the design depth has been reached, the plug in the end of the auger stem is released and a high-performance concrete is pumped through the hollow stem to fill the bored shaft while gradually retracting the auger stem. This keeps constant positive pressure within the shaft, preventing the walls from collapsing, and ensuring the integrity of the pile. Once the shaft has been filled with concrete, a steel reinforcement cage is lowered into the fluid concrete pile for additional structural support.

As piling specialists, we can consult with engineers to design the best piling solution for each site, or work to already-developed engineer-designed plans. For more information, contact the piling experts at Solmer Civil on 0418 497921

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