Helical Piles
OLD TECHNOLOGY RE-ENGINEERED
A helical pile consists of one or more pitched helical bearing plates affixed to either a central circular pipe. Helical piles are screwed into the ground by mechanical torque, applied through a powerhead. attached to an excavator.
The pile is fabricated in an array of sizes, can be installed to any depth and at any angle provided that the soil conditions are tolerable.
Described as one of the most interesting, innovative and environmentally friendly foundation solutions available today and an essential and valuable component to a Geotechnical Engineer.
Download the British Standard relating to our technology
Please also refer to AMSE, EUROCODES, SNip, INTERNATIONAL BUILDING CODE
SUPERFAST
A standard 6m pile takes an average of ten minutes to install. This reduces project schedule and costs
REDUCED ACCESS
ECO FRIENDLY
NO CONCRETE
NO EXCAVATION
NO MUCK AWAY
INTRODUCTION
The helical pile, sometimes referred to as a screw piles or screw anchor, has been used in construction for over 200 years. However, it has only been over the last 20 years that this technology has come to the forefront having been defined as ‘an essential part of foundation engineering’.
Helical piles can be designed/engineered to support an array of structures with numerous problematic subsurface conditions. Their rapid installation often results in a reduced project schedule and cost savings.
Helical piles have gained increased popularity and are being used in many geographic locations more frequently than most deep foundations.
Today Helical piles have been adopted into the International Building Code (IBC) and International Standards/Codes including American, British and European Codes.
BASIS FEATURES
The piles are fabricated steel foundations that are rotated into the ground. The pile consists of several components these are
The lead section comprising of the helix plates is the first section to be screwed into the ground. The mid sections are mechanically connected to the lead section and the subsequent mid sections to extend the pile length in order to achieve the desired design depth. The termination plate section is the last pile section that connects the pile to the structure or pile cap. These termination cap or connection are designed to accommodate numerous structures.
WHY OUR SOLUTION
One of the most important elements of design is to select the solution most appropriate to the specific client and project requirements. We don’t cut and paste from our last project, as every project is unique. We incorporate local knowledge and international experience to evaluate all relevant factors and predict performance to deliver the best solution. We strive on a challenge and won’t rest until we find the best possible solution that encompasses quality, economics, innovation, and efficiency ultimately to satisfy each client’s individual needsSpeed of Installation
typically, a standard 6m pile takes an average of ten minutes to install. This reduces contract time, on site preliminaries, speed to market and road/track closures amongst other factors
No Concrete
No currinng time so loads can be applied immediately
No Spoil
No spoil so no waste to muck away, which is especially beneficial with contaminated soil is present expensive cost of muck away
Environmentally Friendly
By reversing the installation process the helical piles can be removed and then re-used leaving a greenfield site
Workmanship
Less reliance on operator skills unlike a pile rig. Minimal instrumentation required to monitor pile installation which reduces human error and calibration problems
On site Modifications
Variability in penetration depth is achieved by additional pile sections.
No Reinforcement Cages
no requirement for full length reinforcement cages which eliminates the inherant problems.
Soil Verification
Monitoring of soils quality
and capacity during installation, direct
comparison to available site investigation and
preliminary pile tests.
Close Proximity
to trees, services, existing
foundations and buildings. No root damage or
undermining.
Resistant to Tension & Compression
the pile can be used as a tension anchor and soil nail.
Cold Temperature Conditions
unlike
concrete that can only be installed above
freezing point without specialist equipment.
Under & Over Water
by utilising
specialist GTL equipment helical piles are able
to be installed in subsea marine conditions.
Low mobilisation & demobilisation Costs
equipment is delivered by a low loader
Restricted Access
Segmented sections for
reduced head heights – piles can be installed
under pipe racks and in basements.
Negative Skin Friction
can be designed for
reduced negative skin friction for collapsible
soils and soils susceptible to heave/drag.
Reduced Resource
a typical crew consists
of three persons. An advantage on hazardous
sites where mitigating risk is paramount.
Guaranteed Product
quality control of steel and fabrication gives confidence in the quality of the pile prior to installation in the ground.
End Bearing Capacity
the steel helix plate gives very good end bearing characteristics, with very little remoulding of the soil surface due to the installation method.
Soil Variability
Unforeseen variability in soils
can be overcome by the addition of helical
plates or additional sections.
Flexible
Helix plates can be spaced to give particular failure conditions (end bearing or
shaft).
Reduced Environmental Impact
Installation
procedure produces minimal vibration and
noise, allowing installation close to noise
sensitive areas and night time operations.
Less Disruption
Reduced deliveries unlike
the wet trades, means less disruption to
neighbours and other on site activities.
No Liners or Casings
no requirement for piling
through perched water tables or underground
water courses.
Quick Test Results
Preliminary Pile tests and
results can be carried out and received within
48 hours of starting.
Resistant to Tension & Compression
the pile can be used as a tension anchor and soil nail.
Flood Control
piles can protrude above
ground and as such provide an elevated platform.
Accelerated Schedule
If a program requires
acceleration then this can be achieved by
deploying additional power-heads and hydraulic
units.
“Creativity is thinking up new things.
Innovation is doing new things.“
Theodore Levitt (1925 – 2006)
INTERESTING FACTS
- IT’S NOT NEW – it is over 200 years old and has been described as one of the most underrated foundation engineering feats of the 19th century
- Over 2 million HSP’s are installed per year in the UK, USA, China, Japan, Canada, New Zealand, Australia. This number is increasing every year.
- The technology has been used for many high profile projects including the 2012 London Olympics, Brighton Pier, Millennium Dome to mention but a few.
- GTL were the first company to design and install in Iraq and Kazakhstan.
- In 1866 Helical Piles were used as a support to Brighton Pier and in 2013 GTL installed additional piles to support existing.
- Helical piles are extremely good at with standing the affects of earthquake.
- More than 100 screw pile lighthouses have been built along the east coast of the United States and in the Gulf of Mexico.
- GTL are acclaimed experts in Helical pile technology and mentioned in many technical books and literature.
- GTL have been involved, as Consultants, in producing International standards including the British Standard
“We are enormously grateful to you and your team for your phenomenal efforts which ensured the successful delivery of The Summer Party this year. With your support, the party was a tremendous success, whilst also raising significant funds for the Serpentine Gallery. We very much look forward to working together again in the future.”
GTL provides a unique solution to industry and has a product that is safer, enables fast track development, minimum intervention (downtime) and finally is good for the environment as utilises less resources than traditional methods.
Joseph Healy
Engineering Director
GTL showed an excellent performance during the project. With their professional approach and full dedication they achieved remarkable goals and have proven to be one of the best.
Apart from great pleasure, working along side them they demonstrated a wide range of qualities such as talent, dedication, now-how attitude, fast paced working style and more, which is rare in business today.
Vugar Azizov
Project Engineering
It was a pleasure to work with GTL during my time at Karachaganak Petroleum Operating b.v., GTL provided an excellent service and were pro-active working closely with their Client to deliver the best solution to suit the projects needs. I would not hesitate to recommend GTL again.
David Bryne
Project Manager
HISTORY
The first recorded use of a helical pile was in 1836 by a blind Brick-maker and Civil Engineer named Alexander Mitchell. Mitchell was born in Ireland on April 13, 1780, and attended Belfast Academy.The lost his sight gradually from age 6 to age 21.
Being blind limited Mitchell’s career options, so he took up brick making during the day and studied mechanics, mathematics, science, and building construction in his leisure time.
One of the problems that puzzled Mitchell was how to better found marine structures on weak soils, such as sand reefs, mudflats, and river estuary banks. At the age of 52 Mitchell devised a solution to this problem, the helical pile.
In 1833, Mitchell patented his invention in London. Mitchell called the device a “screw pile” and its first uses were for ship moorings. The pile was turned into the ground by human and animal power using a large wood handle wheel called a capstan.
Screw piles on the order of 6 m long with 127-mm diameter shafts required as many as 30 men to work the capstan. Horses and donkeys were sometimes employed as well as water jets.
In 1838, Mitchell used screw piles for the foundation of the Maplin Sands Lighthouse on a very unstable bank near the entrance of the river Thames in England. The foundation consisted of nine wrought-iron screw piles arranged in the form of an octagon with one screw pile in the centre. Nine piles were installed to a depth of 6.7 m by human power in nine consecutive days.
In 1853, Eugenius Birch started using Mitchell’s screw pile technology to support seaside piers throughout England. The first of these was the Margate Pier.
The piers themselves supported the weight of pedestrians, carts, buildings, and ancillary structures. The foundations had to support tidal forces, wind loads, and occasional ice flows. Screw piles also were used to support Blankenberg Pier in Belgium in 1895.
During the expansion of the British Empire, screw piles were used to support new bridges in many countries on many continents.
Technical articles were published in ‘The Engineering and Building Record’ in 1890 and in ‘Engineering News’ in 1892 regarding bridges supported on screw piles.
As a result of British expansion, screw piles were soon being applied around the World.
From about 1900 to 1950, the use of helical piles declined. During this time, there were major developments in mechanical pile-driving and drilling equipment. However, with the development of modern hydraulic torque motors, advances in manufacturing, and new galvanising techniques, the modern helical pile evolved primarily for anchor applications until around 1980 when engineer Stan Rupiper designed the first compression application in the U.S. using modern helical piles (Rupiper, 2000). The Helix (screw) pile design is just as effective in the 21st Century as it was back in the 19th Century. It continues to be installed throughout the World.
