The Government has committed to building a bridge to replace State Highway 25A after it was severely damaged during Cyclone Gabrielle and the Auckland Anniversary flooding.
Video / NZ Herald
The Government has committed to building a bridge to replace State Highway 25A after it was severely damaged during Cyclone Gabrielle and the Auckland Anniversary flooding.
Transport Minister Michael Wood announced today that the Government has taken advice that a bridge will be the fastest, most resilient way forward and will commit the funding straight away.
“A dedicated team of project managers and consulting engineers have been working tirelessly to find a solution. The Government has taken advice that a bridge will be the fastest, most resilient way forward and will commit the funding straight away,” said Wood.
Rebuild costs were still being finalised but the estimated cost was $30-40 million. It would be funded through the Government’s $250 million top-up to the National Land Transport Programme fund to support the recovery.
The washed out section of State Highway 25A will be replaced by a bridge. Photo / Supplied
Construction will begin next month and Wood estimated it would be finished early 2024. Wood said the Government would be exploring seven-day work weeks and working “around the clock” to get the highway open as soon as possible.
“Time is of the essence with this project,” Wood said.
Wood described the road as a “lifeline” for people who travel across the peninsula for work or school.
“Currently increased travel time and cost is causing huge disruption,” Wood said.
Wood also confirmed that the Tapu-Coroglen Rd will be open to light vehicles next month providing more connectivity across the peninsula.
Wood said he was working with local government and communities to develop a package of economic support to help businesses that usually rely on SH25A in the meantime.
Wood said the Government has already supported 400 businesses with grants up to $40,000, and provided tax relief for impacted businesses.
Access tracks have been formed down into the SH25A slip area for the geotechnical investigation contractors. Photo / Waka Kotahi
Wood said business owners told him it will be the fourth summer in a row that there’s been disruption to businesses in area.
Thames-Coromandel Mayor Len Salt said a target date of 2024 will give the community some reassurance.
NZTA general manager Brett Gliddon said the bridge will be the most resilient option against the harsh weather the region faces.
The bridge will be built by a New Zealand-based company to the latest design standards, Gliddon said.
Bridges that had faced damage recently after bad weather on the east coast are old and not as resilient.
He said challenges of the project include slips and water still running through the collapsed areas of the road.
The bridge can be partially constructed offsite, which will protect it against any further weather events that may impact the area of the highway in the near future.
“We will look to do as much work as we can while the road’s closed,” Gliddon said
SH25A was closed at the summit on Friday, January 27, to ensure the safety of road users, when deep cracks formed in the road after ex-Cyclone Hale. The cracked section of the road at the summit then slipped away during the Auckland Anniversary storm event.
Waka Kotahi NZ Transport Agency said earlier that geotechnical investigations were progressing well at the site of the huge slip that closed the road.
Two drilling rigs were on site and if good weather continues, the fieldwork is scheduled to be completed this week.
The surface conditions remain steep and slippery for the work crews.
Waka Kotahi said the investigations are assessing the ground conditions within the slip area and the hillside above.
“Ideally, we want to find stable and strong soils or rock that can support the weight of an embankment or structure without the risk of movement or slipping,” the agency said.
Boreholes are about 50mm in diameter and go to depths of about 20m. Photo / Supplied
The data being collected also helps to determine the amount of excavation needed, slope stability and foundation requirements for the various options being considered. These are all important factors that help determine a solution that can be built quickly and efficiently.
“We don’t know which option is most feasible yet. The right solution cannot be established until the geotech work is complete. We know the rebuild must be resilient and as timely as possible. We understand how critical this highway is for Coromandel residents, businesses, and visitors,” Wilton said.
“Boreholes are being drilled to depths of around 20m to help understand what the ground conditions are like, we’re getting data from different methods — boreholes and test pits”, says Waka Kotahi.
The slip on SH25A now measures around 110 metres across. Photo / Waka Kotahi
“Last week test pits were cut from the sites where we only need to understand the soil conditions at a reasonably shallow depth — e.g. near the side slopes of the slip. They are cut and formed by a digger, are about 2-3m square and are dug to a depth of around 3.5m. They’re good at giving a clear picture of the soil composition.”
The two rigs on site are drilling boreholes, retrieving cores of the soil from greater depths and providing more detailed soil and rock strength information. Boreholes are about 50mm in diameter and enable a core of the soil to be extracted. These are being drilled at the sites of the potential bridge and bypass options.
