Foundation Piling: An Overview
Foundation piling is a type of support for a building or other structure and can be made from a variety of different materials such as steel, wood, concrete or even a combination of different materials. Foundation piling provides stability so it needs to be incredibly sturdy so it can cope with extreme weight and pressure.
As well as different materials, there are also different types of piling available. The first method of piling is referred to as driven piles. Driven piles can be made from wood, steel or concrete and are inserted into the ground using a pile driver. The pile driver causes the surrounding earth the move which results in resistance against the driven pile – and therefore more stability.
Drilled piles have a very wide diameter which means that the insertion site needs to be sizeable enough to accommodate the piles. Drilled piles are commonly used in areas which have very dense, compact or hard layers of earth.
Continuous Flight Auger piles – or CFA piles – do not have any casing which means that the hollow drilling technique fills the hollow auger with concrete. A concrete pillar is then formed once the auger is removed.
Micro piles tend to be made from steel and are ideal for use on smaller construction sites. Micro piles are extremely versatile, convenient and great for use when space is very restricted.
Sheet piling is constructed from interlocking steel barriers which hold back earth and water which allows construction projects, which would otherwise be cancelled, to go ahead
The Advantages of CFA Piling
Continuous flight auger piles (CFA piles) have become a popular choice over the last few years. CFA piles are a cheaper option than other piling alternatives but with careful planning and design, quality equipment and experienced contractors, they can be highly efficient.
CFA piles are a non-displacement pile, which means that the risk of damage to surrounding foundations and underground utilities from ground displacement or densification of sands is largely reduced. Damage is much more common when using displacement piles.
Installation of CFA piles can be carried out with limited noise and vibration. If any problems are encountered during implementation of the CFA piles, then it is a relatively straight forward process to re-drill the foundations and reinstall the pile. The pile group or caps, therefore, do not need to be redesigned.
Different elements of the CFA pile installation process can be monitored using a flow meter. Data that can be recorded includes penetration / uplift per revolution, auger depth, concrete supply per increment of auger uplift during placing, and injection pressure at the auger head.
Advantages of a Continuous Flight Auger (CFA) System
There are several reasons why the use of a CFA system is beneficial. They can be installed quickly and quietly, with low levels of vibrations and are also an environmentally friendly option. Unlike displacement type piles, CFA piles have a very low risk of ground displacement or loose soil that becomes solid causing damage to any neighbouring foundations or utilities.
Another advantage of using a CFA system is that it is possible to monitor the entire installation process of the piles. A flow meter provides accurate data that is then recorded and can be analysed. Information that is collected includes penetration/uplift per revolution, auger depth and injection of pressure at the head of the auger.
The CFA system also has an excellent rate of installation success so it is definitely an option worth considering.