The Continuous Flight Auger (CFA) technique is one of the quietest piling solutions available and is virtually vibration free, making it ideal for working in close proximity to existing buildings, in residential or in environmentally sensitive areas. They can also be installed without the need for casing, bentonite or polymers in both cohesive material such as clay and weak rock and non-cohesive and water bearing soils such as sand, gravels and glacial tills.
CFA Piles are produced by drilling into the ground with a hollow stemmed auger to the required depth or degree of resistance. As the ground is penetrated, the soil travels up the flight and once above ground level is removed by the automated auger cleaner. Concrete is then pumped through the rotary table to the toe of the pile and as the auger is withdrawn pressure is maintained so as to prevent voids being formed or the walls of the pile collapsing in. Steel reinforcement is then inserted into the concrete pile to the required depth.
Our fleet includes CFA rigs weighing between 25 and 70 tonnes which are capable of installing piles up to 28m long with a single flight and achieving load capacities in excess of 2400kN.
We also have many smaller rigs capable of installing Sectional Flight Auger (SFA) piles and these weigh as little as 1.5 tonnes and can install up to 750mm diameter piles in only 3.75m headroom. They are often used to form piles within existing buildings or where access is restricted.
Our highly experienced in-house design team work on projects of all sizes and complexities to minimise the diameter, depth and reinforcing of piles, potentially reducing the cost to the client or the programme implications.
Our capabilities extend to the design and installation of: