- Introduction
- Soil Classification
- Soil Test Probe
- Installation
- Torque Graph
- Downloads
Screw piles were invented in England in 1833 and Chance Pisa (Power installed screw anchors) have been used by the utilities (Telecom and Electrical power distribution) for over 50 years. The extensive testing and research carried out by AB Chance enables ABC Anchors to offer solutions to most screw pile applications using either Helicap software or a combination of the Technical Manual and in field testing.
ABC Anchors and Autoguide, Screw Piles and Installation Equipment
All production or distribution is based on current products in the AB Chance programme.
To ensure we can react to customer demand we hold extensive stocks of PISA (tension only) anchors plus materials to produce larger square and all sizes of round shaft piles. At present our main production covers anchors and piles up to 440kN ultimate capacity. Higher capacity anchors are produced for special situations.
Screw Pile Solutions
Advantages of Screw Piles
Speed of installation – often 10 minutes per pile up to 6 meters long
No wet trades – concrete is not used except for form ground beams or grout
Piles can accept full load immediately after installation
Monitoring of installation torque accurately indicates capacity – problems will show up on installation
As screw piles can be removed very easily they are well suited to temporary uses
Anchors can be supplied galvanised or fitted with cathodic protection for aggressive soil or marine applications.
Screw anchors can be installed at any angle to suit the load
A wide range of terminations are available to suit tension compression and combination loads
Why ABC and Autoguide?
Success in pile installation depends on selection of the correct piles plus use of the extensive range of torque heads available from Autoguide Equipment. In many situations the higher initial cost of a screw pile is more than offset by much faster installation, no concrete (or very little) and no spoil disposal.
To fully utilise the time savings it is essential that the installation equipment is easy to use, fast in operation, reliable and, when used correctly, safe. Autoguide’s experience in developing new methods of torque head mounting and innovative combinations of motors and gearboxes gives pile installers the best possible solutions.
Class 1 soils are difficult to probe consistently and the ASTM blow count may be of questionable value
** It is advisable to install anchors deep enough, by the use of extensions, to penetrate a Class 5 or 6, underlying the Class 7&8 soils.
The column ‘probe values’, refers to torques measured using the Soil test probe available from ABC. This kit enables a single operator to perform a practical test to help determine anchor configurations and performance.
In general standard anchors can be used in soils from Class 8 up to Class 4. Rock anchors will give excellent results in Class 1 & 2 soils. However when subjected to tension loads care must be taken to ensure adequate depth of soil over the highest helix.
It is essential that regular testing of installed anchors is used as a back up to torque monitoring. This is the only way to ensure that installers and specifiers maintain confidence in the system. ABC can supply test equipment for quality control and insist on its use by qualified installers.
The portable Soil Test Probe provides a new dimension. This instrument, portable and
operable by one person, will provide reproducible numerical data related to resistance of the
soil to flow under load. It may be used in soils up to the consistency of hard pan, to any
depth below the surface and without the need to make an excavation or otherwise disturb
the soil.
The probe shown consists of a head on a square shaft with a number of extensions, all of
which may be coupled together. A ratchet wrench with a torque measuring handle is used to
install, remove or take readings. Corner marks at one-foot intervals provide means to determine
the depth below the surface when a reading is taken.
The hub of the probe head is forced into the ground by application of torque acting on the
blade of the probe. Thus the torque required to turn the probe is proportional to the resistance
of the soil to penetration of the hub. It is this property of soil which is of interest in
making an anchor selection in determining the bearing strength – especially for end bearing
screw foundations or footings.
Probe readings can be related back to the general soil classifications to determine anchor
holding capacities (see Soil Classification data above)
For end bearing foundation work, the bearing strength of the soil may be calculated directly
from the probe reading.
This heavy duty probe will withstand torque to 1800 lb inches (200 Nm) on the scale, so it
will not penetrate packed gravel, shale or rock. Thus, for foundation work, other means such
as augering will be required to determine the thickness of the hard strata. When the hard
strata is penetrated, the probe can be used to evaluate the quality of an underlying softer
soil.
Acrobat Reader is required to view our product manuals. If you do not already have this installed, you can download a free copy from the Adobe website.
Class 1 soils are difficult to probe consistently and the ASTM blow count may be of questionable value
** It is advisable to install anchors deep enough, by the use of extensions, to penetrate a Class 5 or 6, underlying the Class 7&8 soils.
The column ‘probe values’, refers to torques measured using the Soil test probe available from ABC. This kit enables a single operator to perform a practical test to help determine anchor configurations and performance.
In general standard anchors can be used in soils from Class 8 up to Class 4. Rock anchors will give excellent results in Class 1 & 2 soils. However when subjected to tension loads care must be taken to ensure adequate depth of soil over the highest helix.
It is essential that regular testing of installed anchors is used as a back up to torque monitoring. This is the only way to ensure that installers and specifiers maintain confidence in the system. ABC can supply test equipment for quality control and insist on its use by qualified installers.
