State Highway 1 Gantry Renewals

Customer: Waka Kotahi NZ Transport Agency

Contract: Design & construct

Location: Auckland, New Zealand

Building Solutions New Zealand & Pacific Islands


  • Trusses
  • Portal Tubular
  • Cantilever Tubular
  • VMS sign renewals                        

New Zealand's Mechanical Division has been fabricating and installing the sign gantries since 2019.  Most recently Fulton Hogan, contracted the team to fabricate and construct a new tubular portal gantry and relocate a cantilever truss gantry 300m as part of the State Highway 20B Upgrade project.

The scope required the team to demolish the old sign’s foundations, taking care not to disturb the existing underground services which were at a shallow depth and couldn’t be removed. The services were the critical gas and fibre lines to Auckland Airport, so there was no room for error.

Working in the road corridor
Once services were safely aligned the team constructed new reinforced concrete pile foundations for the two signs. All the work alongside the State Highway network was carried out at night under traffic management – a single lane closure - to provide a safe work area for the team and minmise disruption to motorists. The final steel sign assemblies were installed using a truck crane. The simple plant option reduced risk and meant the team could install the new signs efficiently and cost-effectively.

Custom fabrication
The digital VMS sign on the cantilever sign also needed replacing and the structure needed modification to accommodate it. The team opted to remove the horizontal section of the truss and complete the modifications at the yard. It was then brought back to site to be installed with the new VMS board. Under the temporary traffic management access and time was tight so this approach was the most prudent way to avoid any issues with the fit.

Safety & security
The team is also experienced in providing access prevention solutions to try and minimise unauthorised access onto state highways for Auckland System Management (ASM).  Some examples of the kinds of steel work we have done are sign gantry ladder guards, gate repairs, lock protection, and custom-hatch designs.  If urgent safety system remediation is required, the team can mobilise and repair structures quickly to minimise potential risk.

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