Continuous Flight Auger Piling (CFA), one of the most commonly used piling techniques, uses a continuous hollow stem auger, drilled into the ground to the specified depth. Concrete is then poured through the hollow auger, as the auger is slowly extracted. Reinforced steel cages are then plunged in to the fresh concrete..
We have a large range of CFA rigs, in a variety of sizes, making us well suited to provide CFA piles for a wide scope of projects and ground conditions; from large diameter to restricted access.
Open bore standard flight augered piling uses a solid auger. Most commonly used in cohesive ground conditions, such as clay, as this allows the pile bore to stay open once the auger has been retracted. Reinforced steel cages are installed and the open bore concreted to form a pile.
Sectional Flight Augered Piling (SFA) utilises open bore or hollow stem CFA techniques, however, the auger is constructed in sections to allow piles to be installed inside buildings or other low headroom environments.
Temporary casings are commonly utilised with SFA open bore piles where the ground requires support for the pile bore to remain open during the installation of the reinforcement and concreting of the pile.
Rotary Borded Piling (RBA) is the process in which the pile is open bored with a telescopic mast, as opposed to full auger string. Where necessary, temporary casing is inserted, to prevent ground collapse and when the founding level is reached a steel cage is inserted and concrete is poured. Temporary casing is removed immediately following the concreting of the pile.
RBA has the ability to drill through most obstructions and is also used when a high load capacity pile is required on restricted sites, as large diameter piles can be drilled in close proximity to adjacent structures and with limited headroom.
Driven piles, also known as displacement piles, are used in non-cohesive soils to transfer loads to layers of soil or rock with sufficient bearing capacity. Driven piles are ‘hammered’ into the ground by either a top or bottom driven hammer. Driven piles are quick to install, and produce minimal spoil, which make them ideal for contaminated sites.
Driven piles can be made out of a variety a materials and are typically pre-fabricated off site, which allows for efficient installation, reducing time on site.
Helical and Screw Piling are prefabricated ‘screwed in’ steel piles, installed by rigs or excavators fitted with rotary hydraulic attachments.
Helical and screw piles are quick to install, and produce minimal spoil, which make them ideal for contaminated sites.. They can also be used for temporary structures as they can be removed and recycled, unlike poured piles.
Self Drilling Micro Piling is a form of Mini Piling (also knows as Pin Piling and Needle Piling). That utilises a sacrificial self-drilling hollow stem steel bar that densifies the ground through displacement during drilling. The hollow stem and aperture around the pile are grouted during installation. Suitable for most ground conditions, the piles are small and light, allowing for use in restricted access sites. Micro piles are also an efficient and economical method of foundation stabilisation. They cause minimal disruption to the building fabric or to the occupants who can remain in the residence while work is carried out.
Rotary Displacement Piling (RDP), similar to CFA methods using a continuous hollow stem auger, however, instead of breaking down the soil for extraction it forces the ground away from the bore laterally. The densification of the ground around the pile bore enables the required load transfer to surrounding ground. RDP piles produces minimal spoil arising making it ideal for brownfield and contaminated sites.
Having our own fleet of rigs in a variety of sizes, included rigs that fit through a standard doorway, as well as the ability for bespoke manufacturing we are able to provide restricted access piles for a wide range sites and in different ground conditions.