SH25/SH25A Thames-Coromandel

13 November 2023

Pre-Christmas opening confirmed for SH25A

State Highway 25A between Kōpū and Hikuai will re-open to traffic in time for Christmas – a full three months earlier than anticipated. 

The route will re-open by 20 December 2023, reconnecting the two sides of the Coromandel in time for the summer holidays.

Getting traffic across as soon as possible has always been the aim for Waka Kotahi.  We know how difficult the highway closure has been on local families, businesses, schools and communities and the impact it’s had on visitors to the region. That’s why, along with our builders, McConnell Dowell and Fulton Hogan JV, we’ve pulled out all the stops.

And our team has done an amazing job - getting it open in less than seven months is a huge achievement given a bridge of this type would normally take 18 to 24 months to design and construct.

We’ve built the 124-metre bridge in record time by being able to use a similar bridge design from another project which allowed us to start ordering materials and begin work before the SH25A design was complete. The precast deck system and lots of overtime and nightwork allowed us to keep all work fronts in sync with each other so we have been able to keep to a very tight programme.  

There is still a lot to be done between now and Christmas – see the next story for our progress.  And once the road is open, there will still be finishing work to complete, so the bridge will open under traffic management at a reduced speed. 

After the holidays the project team will be completing drainage, some earthworks and removal of temporary bracing under the bridge. This work won’t require the road to be closed, but traffic management will be needed from time to time.

We will provide more details of what to expect over the coming weeks.

The cost of the bridge, once everything is finished, is expected to be approximately $43m, under the $50m estimate. 

At the same time, we’ve invested an additional $25m to enable multiple crews to clear slips, replace culverts, and undertake crucial road maintenance work along the rest of the length of SH25A to ensure the whole corridor is up to scratch, safe and more resilient. Getting this maintenance work completed now also means we can avoid further work and disruption for drivers during the busy summer period.

The team take time to celebrate completing the installation of the deck panels.

Weekly bridge update

Last week the team finished installing the 138 deck panels on the new bridge, installing all the reinforcement to stich them together and the three concrete pours needed to lock the deck panels together.

Drainage at the eastern approach was also completed, while drainage installation under the bridge is progressing well.  The stormwater road crossings including wingwall and manhole installation, and swale drains under the bridge were also finished.

Work continues with the soil nailing and mesh installation for the slip face with day and night shifts.

We’re also underway with the new road construction at the eastern approach which involves grading the alignment to the new road profile and building up the subbase and basecourse layers. 

This week, the team will start installing the 52 concrete barriers and are expecting to have the majority of the barriers in by the end of the week. Each of the six- metre-long barriers weigh three tonnes. 

There is still a lot of work to do before opening the bridge, including:

• Soil nailing to stabilise and strengthen the slip face 
• Installing the concrete side barriers and concreting them into place 
• Installing the approach barriers
• Asphalting over the bridge deck 
• Road surfacing and line marking 
• Road signage installation.

Stabilisation work underway at Ruamahunga

Work is underway to stabilise the large slip at Raumahunga Bay on the Thames Coast.

During the works the road will be under stop/go traffic management, with the occasional 'stop/stop' when helicopters are operating.

The boat ramp and its parking area will be closed from Tuesday 14  to Thursday 16 November so our contractor can park equipment and a storage container there. 

The team will make an early start on Tuesday to safely cut down three trees with a helicopter operating. This will require a 20-minute road closure between 5:30am to 6:30am, so the work can be done safely at a time when traffic is light.

We are aiming to have further helicopter activity, to complete preliminary works, on Thursday 16 November.  This will require traffic management  with periodic 20 minute stop/stop closures between 8am to 11am.

This work will continue up to and then after the Christmas break.

Recovery works on SH25

Works began this week to stabilise the underslip at Wharekaho.  Temporary works are underway to widen the road so work can proceed safely with a single lane remaining available for traffic. This operation will work under a stop/go set up.

We are planning to stabilise the area with anchors and protect the base of the slip from further scouring with rock protection, and aim to complete these works before the Christmas break.

Similar work at Coroglen should be completed next week. 

More information

For more information on the SH25/SH25A Thames-Coromandel project, contact us at coromandel@nzta.govt.nz

Visit our website www.nzta.govt.nz/thames-coromandel