CFA Piling
CFA (Continuous Flight Auger) piles are quick to install and offer an efficient, rapid solution for predominantly more lightly loaded structures.
Bachy Soletanche have a large fleet of C.F.A rigs, in a variety of
sizes to offer clients the best value, for a large variety of piling
projects. Our highly experienced in-house design and pre-contracts
teams, are based throughout the U.K., and so have an in depth knowledge
of the most cost effective foundation systems.Recent advances in rig technology have lead to, in the right soils, larger diameters up to 1200mm, or longer piles up to 32m, being installed. Quality has also been improved in recent years with our skilled and experienced site staff and sensitive onboard instrumentation, to monitor performance and quality.
This enables Bachy Soletanche to offer the best value CFA piles at first time of asking.
The installation process of CFA piling
Amplus
offers a comprehensive range of piling systems aimed at supplying the
most appropriate and cost-effective type of pile for a particular site
condition. All piles are installed by fully experienced operators trained to BDA and CITB guidelines.
Piles
can be installed with or without casing, using auger, rotary percussive
or driven methods to cater for most ground conditions.
- Continuous Flight Auger (CFA) piles are from 350mm to 900mm diameter.
- Rotary Bored cased cast insitu piles from 350mm to 900mm diameter.
- Segmental Flight Auger (SFA) piles in diameters from 300mm to 450mm.
- Overburden Drilling System (ODS). These are rotary percussive bored cast insitu permanently cased piles 200mm to 250mm in diameter.
click here to download method statement.
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CFA pile diameter (mm)
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Typical safe working load (kN)
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350
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300 - 400
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450
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750 - 850
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600
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1100 - 1500
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The Continuous Flight
Auger (CFA) piling system provides a quiet low vibration form of piling
that is ideal for providing foundation support in built-up or
environmentally sensitive areas.
Amplus's CFA rigs can
construct piles in most soils including clay, silt, sand and gravel in
high water tables without the need for temporary support systems.
Amplus rigs can
install piles through different soils, obstructions and forming
substantial rock sockets using down-the-hole hammer systems.
These piles are
available in diameters of up to 250mm and in appropriate rock conditions
can provide safe working loads upto 750kN.
Segmental Flight Auger Piles (SFA)
Amplus
offers a range of high capacity small diameter drilled and bored pile
systems including SFA purposely designed to tackle difficult ground
conditions and working in limited space and low headrooms.
Compact and powerful
hydraulically powered piling rigs such as the TD308 and TD610, can
install piles in virtually any location.
Amplus can drill SFA
piles in diameters of up to 450mm and in appropriate soil conditions
can provide safe working loads in excess of 1000kN. Widely used for
refurbishment of buildings, SFA piles are utilised for upgrading of
existing foundations by stitch drilling or underpinning and for the
provision of retention schemes, i.e. basement walls within limited
access and headroom.
The system operates
with very low levels of noise or vibration and is highly suited to built
up urban environments. Piles can be constructed in headroom as low as
2.1 metres.
The pile shafts are constructed from cement-based grouts with cage, bar or other reinforcement appropriate to the application.
Instrumentation
click here to download information on instrumentation pdf file
Constant monitoring is essential to the success of the CFA system.
Amplus has in-cab
instrumentation that allows the monitoring of the movement and position
of the auger digging head as well as the rate of flow, amount and
pressure of concrete delivered during formation of the pile shaft.
The information is
stored on the in-board computer which can be programmed and interrogated
remotely from the head office providing a permanent record of each pile
constructed and full assurance of quality.
Reinforcement
The reinforcement cage has to withstand the rigours of placement through the recently pumped high slump concrete.
The CFA Foundation
Piles are generally reinforced with a rigid four or six bar 4 or 5 metre
long cage. Full length cages are employed in embedded wall piles and as
and when required by the design.
Concrete cover is afforded to the reinforcement by the effective use of spacers clipped onto the main bars.
Pile Testingclick here to download Integrity Pile Testing method statement.
click here to download Maintained Load (vertical compression) Pile Testing method statement.
SITE INVESTIGATION
Amplus is an Associate Member of the Association of Geotechnical and Geoenvironmental Specialists
Amplus is a member of the ECO-ACTIVE BUSINESS environmental accreditation scheme
Amplus drillers are trained in accordance with BDA and CITB guidelines.
Generally the following site investigation techniques are employed for the majority of projects:
Trial Pitting
Window Sampling and Dynamic Probe Testing
Rotary Cored Boreholes
Rotary Percussive Boreholes
Trial Pitting
Trial pitting can be carried out by a variety of methods from hand dug
pits to machine excavated trenches. Trial pitting is generally carried out to a maximum depth of 4.5m with standard excavation plant and, depending on soil conditions, is generally suitable for most low rise developments.
All trial pit investigations are supervised by experienced engineers with a thorough understanding of geology and soil mechanics.
Additional testing in trial pits can include soakaway testing, CBR testing and in-situ strength testing. back to top
Window Sampling
Window sampling is carried out by hand held pneumatic samplers. Window sampling is particularly suited to restricted access sites, contamination investigations, and where disturbance must be kept to a minimum. back to top
Boreholes
Boreholes are a common method of site investigation. Using a vehicle-towed rig most sites can be investigated. In-situ testing techniques including Standard Penetration Testing, Permeability Testing, Borehole Vane Testing and Packer Testing can all be carried out in the boreholes in order to provide information for geotechnical design. Continuous disturbed and undisturbed samples are retrieved from the boreholes for inspection and logging by engineers and subsequent testing in our laboratories.
Rotary Cored Boreholes
Rotary drilling techniques are employed where boreholes are required into very dense gravel or bedrock. Samples of bedrock are recovered in seamless plastic tubes for subsequent logging by a suitably qualified engineer and for laboratory testing.
Amplus owns versatile drilling rigs, such as the Fraste Multidrill XL Max rig, and the Fraste PL rig that can recover high quality core samples in both soil and rock conditions.
METHOD STATEMENTS FOR SITE INVESTIGATION
Click below to download the following method statements:
- Excavation of Lead Pits
- Trial Pits
- Boreholes - Rotary
- Boreholes - Rotary Percussive with Slotted Casing
- Open Hole Flight Auger
- Dynamic Sampling
- Piezometer Installation
- Locating Cables with a Cable Avoidance Tool
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GROUND INVESTIGATION CAPABILITY STATEMENT IN ACCORDANCE WITH BS5930 Site
Investigation is undertaken using a light Trailer-mounted Fraste PL rig
to undertake borehole ground investigations. This rig permits the
recovery of a continuous core sample of soil and rock from the ground
surface to completion depth.. Drilling A dry core drilling technique, utilizing a tungsten-set cutting tube, is used to penetrate soft materials with drilling diameters ranging from 128mm - 84mm. Drilling can be vertical or inclined. Diamond core drilling begins automatically on refusal to dry core drilling giving high quality rock cores. Dry core drilling can be resumed after diamond core drilling, should soft ground conditions recur. The continuous core is ideal for logging, for checking depths, and as evidence of performance. Sampling 70 mm diameter sample tubes (U-70) are interchangeable with core barrels, so undisturbed sampling is possible at any depth without reaming out the hole. Testing Standard Penetration Testing (SPT) can be carried out in the borehole. Down hole testing and instrumentation, gas and groundwater monitoring and sampling, and inclinometer monitoring are all possible. Field Testing A range of testing is available including piezometers from groundwater monitoring, magnetic extensometers for settlement measurements and plate load tests. Laboratory TestingGeotechnical laboratory testing to BS1377 and analytical contamination testing is undertaken in the UK. Reporting Comprehensive reports including borehole logs and recommendations are available. back to top |
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