State Highway 25A Taparahi between Kōpū and Hikuai has officially reopened, months ahead of schedule and in time for the busy holiday season.
A severe storm in late January 2023 caused a substantial 115m-long and 20m-deep slip on State Highway 25A Taparahi between Kōpū and Hikuai, leading to road closure. NZTA contracted Fulton Hogan and McConnell Dowell supported by Beca and Tonkin + Taylor to swiftly reconnect these communities and the broader Coromandel region.
Initial estimates suggested that reopening the road would likely take over a year. Following a huge collaborative effort by the entire project team, the road has now reopened months ahead of plan and in time for the busy holiday season.
"The reopening of this road will have a hugely positive impact on the local community. Local businesses really suffered from the impact of COVID-19, which kept holidaymakers away from the Coromandel Peninsula. This was followed by bad weather and then the closure of the road, severing access across the Peninsula, impacting locals and their day-to-day life. To have this vital link back in action for the Christmas holidays is the best gift local people and businesses could have hoped for this year," Beca General Manager - Transport & Infrastructure Andrea Rickard says.
In advance of the storm, Beca's geotechnical team had been monitoring this stretch of road due to a number of slips in the wider Coromandel region. The heavy rain caused instability and deep cracks, and the team recommended to NZTA the highway should be closed. On 27 January the road was closed, and on 30 January NZTA confirmed the highway had completely fallen away.
After analysing several potential options to repair the connection, NZTA confirmed a bridge was the optimal solution based on the ability to replace the connection within the shortest timeframe. This required an innovative, collaborative approach in the procurement, design and construction of a reliable solution, and a delivery approach that incorporated several transformational initiatives in New Zealand's infrastructure sector.
About the project
Aerial view of the slip and bridge construction in mid-November 2023.
Aerial view of the completed bridge in mid-December 2023.
At the heart of this project is a 124m-long, 3-span steel composite girder bridge, over 15m above the slipped area.
Several key initiatives were essential to delivering this project at pace:
- using offsite construction methods - most bridge components were constructed offsite and assembled onsite, minimising risk and saving time.
- drawing on previous design experience - leveraging proven design experience from projects like the Takitimu North Link helped the team deliver a reliable solution that saved time in design, review and construction.
- simultaneous design and construction - design work was broken down into smaller stages, allowing for construction to run at the same time.
- removal of design dependency - to enable design and construction of elements to progress at different paces.
"This project is an example of what can be achieved when there is a clear vision and true collaboration. It's not just about rebuilding infrastructure, it's about reshaping how we approach and execute projects, setting a new standard for efficiency and collaboration in the New Zealand infrastructure sector." - Andrea Rickard.