The bridge deck comprises 54 concrete segments, each cast in situ (on-site) using a balanced cantilever method. To build this type of bridge, construction devices called form travellers are required so the teams can pour the concrete segments out from each pier.
When two sections of bridge deck become close to each other, a stitch pour is required to connect them. The team has completed two stitch pours and are now preparing to stitch together the remaining two sections out from pier three before the end of the year.
By December, the bridge should be structurally complete, with final touches such as barriers still to be installed.
The completion of Parahaki Bridge is a massive achievement considering the complexity of building such a large structure over a river, which is also a fault line, and in an area with challenging ground conditions and strong winds.
Just a few metres north of Parahkai Bridge, the project’s second-largest structure, the Eco-Viaduct, is also nearing completion. The team has almost finished installing the barriers on both sides, with finishing touches to be done before the whole structure is completed by early 2025.
The completion of this bridge is another major achievement, with the team having to overcome significant engineering challenges to get it built. These include encountering unprecedented artesian water pressure, which delayed construction of the piles for about 15 months.
Despite these challenges, the team has worked incredibly hard to make up time, and the bridge is on track to be completed on time.
Elsewhere around the project, the pavement crews continue to make great progress constructing the road, with more than half of asphalt placement complete.
Other parts of the road are still seeing the lower layers of the pavement being laid, but 97% of the alignment is now covered with pavement aggregate.
Teams have also started placing layers of stone mastic asphalt (SMA), the final surface layer which provides additional skid resistance.
Work begins on minor features
While many of these updates have focused on bigger aspects of construction, there are also a number of small yet important features that are currently under way on the site.
One of these is the installation of electronic variable message signs (VMS), which alert drivers to things like accidents, roadworks or adverse weather conditions.
The VMS boards are connected to a weather station, wind sensor and visibility sensor to ensure road users are getting relevant information about things that may affect their journey.
Te Ahu a Turanga will have two VMS boards – one positioned near Parahaki Bridge at the western end, and the other near the Woodville roundabout at the eastern end.
Teams are currently building the foundations for these signs – which are nearly 5m wide and 2.5m tall – before the posts and boards are installed over the next few weeks.
Another piece of minor work is the installation of street lighting at both roundabouts.
Lighting has already been installed at the western roundabout, while the Woodville roundabout lights will be installed by the end of the year.
Other works like wire rope barriers and lane marking will be completed over the coming months as the road surface gets completed.
More information
If you want to learn more about the project, head to www.nzta.govt.nz/projects/te-ahu-a-turanga/ or visit the Woodville Community Library and Information Centre for the latest flyover, project updates and the Drive the Highway simulator.
