The process of forming a CFA pile is completed in one continuous operation, using instrumented piling rigs to monitor the pile construction process in real time as the auger is progressed to depth, and whilst concrete is being placed.
The CFA piling method is fast and efficient, generating low levels of noise, and is virtually vibration free.
From start to finish, what is the process of CFA piling?
Step 1 – Prior to the rig arriving to site the client surveys the area for services, prepares a suitable working platform at top of foundation level, and drives a numbered pin into the working platform at each pile position.
Step 2 – A health and safety briefing will take place, the rig will be prepared to work, and moved to the first pile position.
Step 3 – The auger is positioned over the setting out point and zeroed at working platform level. The auger is then progressed to a predetermined designed depth, pausing occasionally to bring spoil to the surface.
Step 4 – Readymix concrete will be delivered to site and pumped to the rig using a system of hoses connected to the top of the auger. The rig operator begins extracting the auger string, ensuring a constant head of concrete is maintained within the auger to avoid the risk of borehole collapse during construction. This process is fully computerised in CFA rigs, providing the rig operator a continuous profile of pile diameter during auger extraction.
Step 5 – The attendant excavator clears spoil from piling mat level, exposing the fresh concrete at the head of the pile.
Step 6 – A reinforcement cage, meeting the design requirements, is plunged into the fresh concrete, to provide fixity between the piles and reinforced concrete foundations.
When is CFA Piling used?
CFA piling is widely used on projects ranging from residential housing, commercial development & refurbishment, to large scale civil engineering projects, and many more. They are equally suited to piled raft slab and traditional ground beam and pile cap applications. In addition to the construction of bearing piles, CFA piling methods are equally well suited to the construction of contiguous, secant and king post embedded piled retaining walls.
Using our CFA rigs, equipped with pull down/crowd function and rock augers, it is possible to install CFA piles through Weak Rock formations, avoiding having to revert to more expensive percussive drilling or rotary bored piling methods.
To get a better understanding of when CFA piling is used, check out our case studies pages.
Our Piling Rigs
Our rigs are equipped with on-board instrumentation systems to ensure high quality pile construction and record keeping.
Our current augered piling fleet consists of:
Comacchio CH 450
You can find out more about our rig collection on our fleet page.