Screw Piling

SCREW PILING

Above is a image of screw piles.

Below is a image of the screw piles being driven in.

What is a screw pile?

It is a circular hollow section of steel (shaft) with one or more tapered steel plates (helix's) strategically welded to the shaft which is in turn wound into the ground using rotary hydraulics for the purpose of compression piles and tension anchors. The benefits include the speed of operation, vibration free installation and greater profits. The system is uniquely simple and offers a cost effective alternative to traditional deep foundation techniques. Common construction equipment can, at low cost, be modified to install screw piles. The system is environmentally friendly and restricts potential damage to adjacent structures by eliminating vibration during installation.

Connection to footing:

Screwpile connection to a typical pilecaps and footings is via either Y-bars placed through the top of the pile or e-flanges. Both are left exposed into the cap / footing.

The advantages of screwpiling are:

• Vibration free installation (no interference to adjacent buildings/structures)
  
• Very fast installation (actual pile installation average of approx. 5 minutes
  
• Minimal noise disturbance to adjacent environments
  
• No de-watering
  
• No concrete
  
• No Reinforcement
  
• No spoils
  
• No liners
  
• Versatile
  
• Re-Usable

Applications:

• replacing bored piers
  
• Replacing blinding concrete
  
• Replacing concrete pads and stumps for timber floors
  
• Angle of repose for easements and sewers
  
• for protection of tree roots and as root barriers
  
• for underpinning new or existing structures
  
• for eco-sensitive sites
  

The pile consists of a high tensile 350 to 400 Grade steel shaft, with a single or multiple Helix Plate welded to the base of the shaft and a point of attack "bit" at the end, to assist in penetrating the soil profile. The pile is screwed into the soil profile by a hydraulic drive motor which is suspended off the boom of the excavator. 
A pressure gauge is mounted in the cab for the operator to read the "torque" being generated as the pile is screwed into the soil profile. The torques are measured and recorded by the installer on the engineer's project log. 
The design requirements for the torques are test proven from soil bearing capacity to torque relationships which are related to Static Load results and C.P.T. comparisons.

Information sourced from: http://www.pilingsystems.com.au/what_is.shtml and www.instant.com.au/