Engineers

Screwpile Specification

Screwpile specification covers the quality of component materials and work procedures in accordance with the relevant Australian Standards:

Quality of Steel

Screwpile components are manufactured from both AS1163 G350 and G250 yield strength steel depending on the component.  Simplified the yield strengths for the main components are:

  • Pile Shaft G350
  • Helical Bearing Plates G250
  • RET Cutting Tips & Plates 780S
  • Other G250

Notes: There are some screwpile copiers who have used second hand unidentified steel as pile shafts in their manufacture.  The practise of using these material, in our opinion as well as others, does not conform to Australian Standards and as such should not be used.  See the attached report for further information and findings.

Welding Procedures

Quality welding processes is one of the critical manufacturing issue.  Incorrect welding procedures has the potential to cause weld failure between the helecies and the piling shaft under full structural load situations. Due to the slender nature of screwpile shafts critical helical clearances, weld quality, fillet weld size and number of passes are paramount.  Inspection of a number of copy screw foundation products do not conform to these critical areas.

Helix and Pile Shaft Selection

Helical shape diameter and plate thickness along with the correct CHS diameter and wall thickness selection are critical to screwpile design performance.  CHS section and wall thickness needs to also be considered as part of the installation process.  For example the CHS section required to support the pile load capacity is relatively small but the installation of the pile is likely to encounter difficult ground so the section will need to robust enough to resist deformation during the installation process in tight or hard ground. See a compeditors product photo herein which has failed during installation.  This steel screw in foundation was installed and this was the condition it was in once it was removed.  Clearly this screw foundation had zero load capacity. Note the thin 3.2mm wall thickness and stretched drive end further reducing wall thickness.

Installation Procedures

Screwpile are only to be installed by qualified installation operators who have conducted Screwpile Australia's "Accredited Screwpile Installation Procedures Course" and in strict accordance with the design engineers specifications and intended outcome.  Detailed piling installation logs are to be completed and recorded so as to satisfy the requirements of AS2159 Piling Code.  Without these requirements being met it is not possible for Screwpiles Australia's certifying engineers to provide installation certification.

Documentation

 

Engineering and Certification

 

For more specific details please email us directly.