School access from SH 1 enabled by new bridge
Whangārei Boys’ High School Bridge

The $50M redevelopment of Whangārei Boys’ High School (WBHS) included replacing around 80 percent of the school’s antiquated buildings that were in poor repair, with modern, state-of-the art learning facilities and a new bridge to allow easy access to the site directly from State Highway 1 (SH1).

United Civil was contracted by the Ministry of Education (MOE) to build the new 45m two-lane road bridge, along with 100m of access road from SH1 into the school grounds. After the contract was awarded, MOE expanded United Civil’s scope of works to include the placement of preload and granular pads to the foundations of the new buildings in addition to the bridge works.

This redevelopment was undertaken within the grounds of the existing school, which meant that one of our main challenges was to ensure minimal disruption to students and the elimination of health and safety risks that construction work could otherwise pose. Our construction methodology avoided the need to traverse through the other areas of school by constructing a temporary bridge to establish access from the eastern embankment. The precast units for both deck spans were put in place from across the river using a 250 tonne crane.

The original construction schedule would have seen the bridge completed ahead of the major construction work on the school buildings, however the Covid-19 lockdown in March 2020 delayed the start of the project. To keep the project timing on track, our team worked on the bridge access alongside and in parallel with the construction contractor’s work on the school buildings and grounds.

Being so close to SH1, the establishment and transport of large cranes and the deck spans to the staging area required temporary road closures. United Civil liaised and communicated with stakeholders to minimise disruption and ensure the process ran smoothly.

Key features and innovations included:

  • Temporary bridge providing access for general construction traffic
  • New entrance off SH1 and approximately 100m of access road
  • Installing a 45m long, two lane, two-span road bridge
  • Three 750mm driven steel casings filled with reinforced concrete for each foundation pile
  • 16 single hollow core post tensioned deck spans
  • Diversion of underground services