Easter Glentore Wind Farm

Easter Glentore is a wind farm situated between Glasgow and Edinburgh. This project entailed the jacking of two substation transformer units back to their original level.

The very poor ground was a mixture of soft undisturbed peat along with 5.5m of infilled stone that had over a period settled and caused the substation units to subside on one side. The movement of these units, both weighing in at around 12t was putting the underground electricity cables which are fed from the wind turbine at risk of damage.

ABC Anchors were asked to install screw piles along the subsiding edge of both substation units and bring them back to level using underpinning jacking brackets.The project needed careful planning due to the potential damage to the underground cables during the pile installation and the cost of having the wind turbine shut down for longer than necessary.

As always with the underpinning process, careful excavation to expose the footings was the first operation. The units were both set on 300mm thick concrete slabs so once the underside of these had been exposed localised pockets could be cleared away under the edge of the slab to allow for the jacking plates. The piles could then be installed using the ABC 500X torque head mounted on a 5t excavator. 4 piles were used on the smaller unit and 7 and the larger one. All the piles needed to be installed to 4kNm of torque which meant they were 6m deep in order to penetrate the hard undisturbed layer which started at 5.5m.

Once all the piles were in place the jacking brackets could be fitted and the jacking up process could begin. Care is always taken during this process to ensure the structure is loaded equally and no damage is incurred.

40kN hydraulic jacks were used on each pile making the leveling of the units a simple operation. With the piles all preloaded equally and the units back to level the jacking brackets could be locked in place using the M16 threaded bars and the jacks removed.

Finally the excavated soil is replaced with a type 1 scalpings and compacted to ensure there is no movement between the piles and the foundation.

Customer Comments

This was our first time using a screw piling system and I would highly recommend it, I would give the guys a 10/10!

Darren Hendry

Installation Packages

Package Choices

We can offer several packages for the supply and installation of our screw piles.

We can supply the piles and recommend an installer who will offer a full installation pile log with guarantee of work.

We can supply the piles and hire out the installation equipment for you to install.

Training courses at our premises or onsite (How to correctly use our equipment to install screw piles).

Onsite guidance.


Torque Heads

400H
400H

500X / XG
500X / XG

650H
650H

1600X
1600X

2500X / XG
2500X / XG

All our torque heads are manufactured by our sister company Autoguide Equipment and can be either purchased or hired from us. This can be on a daily or weekly basis.

Downloads

ABC Torque Heads

Screw Piles

Screw Pile Capacities and Installation Equipment

  60Rrangeb 76RRangeb 89R-39336b
Screw Pile Range 60R 76R 89R
Torque Head Model 400H 500X 650H 1600X 2500X
  400H 500X_XG 650H 1800X 2500XGb
Max Torque 4kNm 5kNm 6.5kNm 16kNm 25kNm
Machine Type Hand-held Excavator Hand-held Excavator Excavator
Ultimate Pile capacity
(un-factored) torque
120kN 150kN 180kN 450kN 625kN
Safe Working Load
(2.5 FOS)
48kN 60kN 73kN 180kN 250kN
Specification Sheet
(PDF)

Un-factored Load - A Maximum load that the Pile will take before deflection exceeds standard limits.

FOS - Factor of Safety - is the ratio between the un-factored load and the working load

Safe Working Load -The actual load the pile is taking when the building is in place

All machines offer torque read outs, allowing the pile capacity to be calculated instantly.

Screw Pile Specifications

SPECIFICATION DEFINITION 60R 76R 89R
Shaft Diameter Diameter of the screw pile shaft excluding helices 60mm 76mm 89mm
Wall Thickness Thickness of the screw pile tube wall 6.35mm 9.5mm 9.5mm
Torque Limit The ability of the pile to transmit torque is always the limiting factor. This is therefore the ultimate practical pile install torque capacity. 4kNm 16kNm 25kNm
Ultimate Strength Single Helix The load which can be supported by a single helix- most piles use multiple helixes, but if a single one has to support more load (although non standard) this can be accommodated. 90kN 160kN 220kN
Empirical torque factor KtKt m-1 The “Empirical Torque Factor” expressed in metric units when torque is measured in kNm and force in kN. Its value decreases as pile diameter and helix plate thickness increases. This is due to a combination of skin friction and the energy needed to displace the soil. 30m-1 28m-1 25m-1
Tube Specification S355 HFS DIN1629 ST52 or Equal S355 HFS
Helix Specification BS4360 43A BS4360 43A HRMS BS4360 43A
Fasteners Specification Metric M16 GR8.8 Metric M20 GR8.8 Metric M22 GR8.8

Pile Life/Corrosion

In most conditions, provided the top 2 metres are galvanised the pile life will be in excess of 100years. Where the soil resistivity is less than 10 Ohm– further steps must be taken. This means salt water, wet peat and where soils are subject to saturation. For more information and literature please contact us.

The estimated life is based on the assumption that a loss of 40% in thickness is acceptable without adverse effect on structural integrity. The atmospheric exposed areas of the piles are coated with high build zinc rich coating system or galvanised. There is a safety factor of x2 included for the anode design to take account of variances in corrosion conditions and ground resistivity.

Ground Resistivity(Ohm-m) Corrosion rate based on Uhlig data mm/yr Estimates life with corrosion protection (years) Corrosion protection methods, required for top 2m section of Pile. (Min 9.35mm wall thickness) Estimated life with additional corrosion protection* (years)
Less than 5 0.1-0.2 18-37 Zinc rich coating
4 x 20kg galvanic zinc bracelet
100
5-10 0.033 80+ Zinc rich coating
4 x 20kg galvanic zinc bracelet
100+
10-50 0.025 100 Zinc rich coating 100+
50-100 0.018 100+ n/a 100+
Greater than 100 0.014 100+ n/a 100+

Wind Turbine installation

Wind Turbine installation

ABC offer a wide range of Screw-Piles including the Conical anchor system, ideal for wind turbine installations.

Features

 Cone shape can resist lateral loadings up to 5KNM.*

 60mm Anchors can resist axial loadings up to 120KN.*

 Specially designed plates allow adjustments to ensure vertical towers, with around 75mm movement in all directions.

 Anchors can be extended up or down to achieve desired installation torque.

 

Wind Turbine foundations have to cope with a combination of alternating vertical, over turning moment and lateral loads.

The ABC Conical anchors, generally in multiples of three or four, can be installed quickly in most soils ranging from very soft to chalks to a consistent capacity.

Measuring the installation torque is a reliable and proven method of establishing the capacity of a screw pile and gives great confidence to specifiers.

Autoguide Equipment supply and manufacture installation equipment, including hand-held and excavator mounted torque-heads as well as the Postmaster range of vibrating post drivers. In combination with ABC anchors Screw Piles, these systems provide fast, safe and accurate installations which help save time and cost for contractors and customers.

 

Downloads

088icon

Wind & Solar Leaflet

Equipment Hire

Screw Pile Installation Equipment Hire

ABC Anchors offer a range of Autoguide’s screw pile specific torque heads for hire. All torque heads come equipped with torque gauge for driving screw piles to the required installation torque.

Installers for 60R Piles

400H Hand-held Anchor Drive

Our 400H portable anchor installer is available with or without the hydraulic power pack and is ideal for use in confined spaces or areas of limited access. We hire this machine for installing our 60R screw piles, to accommodate loads up to 48kN.

500X / XG Torque Head

We have a range of mounting brackets to attach the 500X to excavators from 1.5 to 6 tonnes. This allows anchor installation at a wide range of angles. When access is not an issue, installation using the 500X instead of our handheld equipment allows our 60R screw piles to accept loads up to 60kN.

400H
400H

500X / XG
500X / XG

Installers for 76R Piles

650H Hand-held Anchor Drive

The 650H portable anchor installer is available with or without the hydraulic power pack and is ideal for use in areas of limited access much like the 400H. This larger handheld machine can accommodate loads up to 73kN with our 76R screw piles.

1600X

The 1600X is the torque head of choice for installing our 76R screw piles, accepting loads up to 180kN. It can be mounted using a range of brackets to excavators from 4 to 7 tonnes.

650H
650H

1600X
1600X

Installers for 89R Piles

2500X

The 2500X is an excavator mounted torque head for use with 89R screw piles. Our largest pile can accept loads up to 250kN and must be installed using an excavator from 4 to 10 tonnes. The torque head is shown here with the Gimbal bracket, which allows installation when head room or the excavator boom arm length is an issue; mounting on the side of the head rather than the top.

2500X / XG
2500X / XG

Soil Test Probe

The soil test probe is used to determine the soil conditions on site where no soil investigation information is available. Torque readings are recorded at 250mm intervals to provide an indication of the properties of the soil. These readings can be easily correlated against SPT value charts to determine the soil type and it’s suitability for accepting screw piles.

As a general rule, screw piles are not designed to penetrate solid bedrock, nor are they able to penetrate through obstructions such as boulders or buried concrete. However most other soil types are acceptable.

Being hand driven or with a high torque battery drill, the data produced allows the engineer to design the most suitable pile configuration for the calculated loads.

On many small projects use of this equipment can result in overall price reduction (especially compared to a full ground investigation), with a high level of confidence in the finished result.

Soil Test Probe
Soil Test Probe

Bowler Energy Solar Array

Bowler Energy are a Nationwide installer of wind and solar energy systems using a variety of ABC Anchors’ solutions. In very soft or very hard clays they use ABC 60R screw Piles.

 

The helical screw piles are installed to specific minimum torques to ensure the integrity of the array – even in the severe weather we have been experiencing lately!

Installation of a ‘Caterpillar Walkway’ at Thames View School.

ABC Anchors supplied and installed the screw piles for a tubular steel framed canvas covered ‘Caterpillar Walkway’ at Thames View Junior School.

For the installation localised pockets of Tarmac were removed from the playground to allow 12qty 60R Screw Piles to be installed. One pile for each canopy foot.


 

 

Due to very poor ground conditions and relatively high Compressive/Tensile and lateral loads requested, the piles were installed to a depth of 4m.

The piles consisted of a 60R 2m lead section with 8” 10” helix, a 1m conical extension and a 1m 240mm diameter peat pile extension. These larger diameter top sections were installed to withstand the high side loadings.

All 12 piles were installed to between 3 & 4kNm using an ABC Anchors 500X torque head fitted to a 5t excavator. This installation torque equates to an axial load of between 90-120kN/pile.

All 12 piles were installed with little disruption to the school playground and with little soil away.

Connection from pile tops to steel canopy legs consisted of matching square flange plates with 4 x M16 bolt holes in each plate.

Grand Designs – New Build Screw Pile Foundations

ABC Anchors recently featured on Channel 4’s Grand Designs Programme,shown installing 60R screw piles with the ABC 500X torque head attached to a 2.5 tonne excavator.

The complete piling process took little over a day to install and offered accurate foundations which could be built on immediately.

The main structure was a 5 bedroom family home built to extremely high standards of environmental performance by FACIT HOMES using the latest onsite mobile production facilities.

Eco-Friendly foundation installed in 1.5 days

The whole project from breaking ground to moving in took just 7 months!

Broadbridge Heath Roundabout sign

A screw piled foundation proved to be the best solution for this round-a-bout sign in Broadbridge Heath. The ground where the sign is situated had numerous electric and communication cables running through therefore concrete foundations would not have been possible.

The sign itself was not heavy but the foundations had to withstand high lateral loads imposed by potential high winds, 4 screw piles were installed beneath a steel grillage all set below ground level.