SH20 to Airport – Manukau, Auckland

SecuGrid® – Multi Directional Geogrid


MHX Kirkbride Alliance


Fletcher Infrastructure & Higgins


Beca and Fletcher Construction Co (FCC) temporary works engineers




Grant Suckling

Technical Sales


SH20A is the primary route to and from Auckland Airport and forms a strategic link between SH20 & SH16, the Airport Business District and the greater Auckland area. The NZ Transport Agency’s upgrade of SH20A to motorway standard has provided a safer, more reliable route to and from the airport and has increased freight efficiency around South Auckland.


Cirtex worked with FCC temporary works engineers to design working platforms over very weak ground conditions for the safe operation of heavy machinery. Cirtex also provided an alternative slope stability solution, saving significant time and money.


Two layers of SecuGrid were used to reinforce the gravel raft providing efficient load distribution of the stresses transferred from the heavy plant and equipment. As an alternative to sheet piling Platipus Anchors were used in conjunction with CombiGrid to stabilise steep cuts.

The products used provided the following benefits to the project:

  • Platipus provided an anchor system that was cost effective in comparison to other systems
  • CombiGrid and Platipus anchors were chosen to stabilise steep cuts as they used readily available equipment for installation
  • SecuGrid assisted in providing an efficient and safe working platform

Products used in this project

SecuGrid® Multi-Directional Geogrid

SecuGrid is designed to interlock with the aggregate placed above it to provide stabilisation and bearing capacity improvement to soft subgrades and also reduce rutting in a pavement application.

Platipus® Civil Anchor Systems

Platipus percussion driven mechanical anchors are a unique, modern and versatile device that can be rapidly installed in to most displaceable ground conditions.

CombiGrid® Multi-Directional Geogrid Geotextile Composite

CombiGrid combines all the functions of a geogrid and geotextile in one single product and is ideal for reducing aggregate depth requirements and providing a stable platform on soft ground.

DuraForce™ AS Series Nonwoven Geotextile

DuraForce AS series geotextiles are manufactured and tested to exact quality standards and rated according to the NZTA F/7 specification for geotextiles. Available in a range of grades depending on the particular engineering application required.

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