'The beast': massive swing bridge a challenging build

An illustration of a completed Aoraki/Mount Cook swing bridge that will span 189 metres across...
An illustration of a completed Aoraki/Mount Cook swing bridge that will span 189 metres across the Hooker River on the upper section of the popular Hooker Valley Track. IMAGE: DC STRUCTURES STUDIO
The first images of the country's longest swing bridge have been revealed, and the project has caused a few headaches, the Department of Conservation says.

Contractors refer to the bridge, being built in Canterbury's Aoraki/Mount Cook National Park, as "the beast" for its sheer size - but also because of unseasonal bad weather they have had to battle recently.

The bridge will span 189 metres across the Hooker River on the upper section of the popular Hooker Valley Track. It replaces an existing swing bridge which had to be closed in April this year due to riverbank erosion near the bridge supports.

Construction on the new one began in August and since then, Mother Nature has thrown everything at the team working on site, Doc said in a statement today. 

Workers have had to battle the elements, with strong winds blowing sheds over. PHOTO: ASH ROGERS
Workers have had to battle the elements, with strong winds blowing sheds over. PHOTO: ASH ROGERS
Ash Rogers, construction supervisor from Abseil Access, has worked on many challenging bridge builds around the Pacific and in New Zealand, including Southland's Milford Track - but this one takes the cake for stress, he said.

“Spring really threw absolutely everything at us, to be honest. We had heavy snow and ridiculously strong winds that blew sheds and equipment down steep banks.

Snow discovered inside a shed. PHOTO: ASH ROGERS
Snow discovered inside a shed. PHOTO: ASH ROGERS

"Mentally it was tough for the staff working in such extreme conditions. The weather can change many times a day up here.  We have our own weather station, and an average day has winds of between 80 and 150 kilometres per hour blowing.

“It’s a very special place to work in and sometimes you want to pinch yourself with the view, but there are many times, when the wind gets up and you just pray for calm fine days in a row where we can get the work done without worrying about the elements."

The team have just finished drilling of the main bridge support masts and are now completing wind-anchor drilling and concrete foundation pours. They hope to start work assembling the bridge cables early next year. 

The engineer and architect behind the unique bridge design, Dan Crocker of DC Structures Studio, said getting to design New Zealand’s longest span footbridge in such an iconic location was an amazing opportunity.

“It’s been designed with state-of-the-art pedestrian vibration and wind dynamics due to the unique location. We wanted a design which was a “light touch” in such a pristine landscape, so that visitors can revel in the experience and thrill of such a large crossing while appreciating the magnitude of the surrounding peaks.”

It is hoped the new bridge will be open by autumn next year.  IMAGE: DC STRUCTURES STUDIO
It is hoped the new bridge will be open by autumn next year. IMAGE: DC STRUCTURES STUDIO
Doc's Aoraki/Mount Cook operations manager Sally Jones said it would be an exciting next few months seeing the bridge take shape.

“The new swing bridge will become a destination in its own right for people who love getting out naturing. The design is spectacular, and visitors will find crossing it exhilarating because of the length.

"The construction team are doing an awesome job, as the past few months have been really full on, weatherwise."

It was hoped the bridge would be open towards the end of autumn next year, she said.

“The weather has put things a little behind schedule, but fingers crossed, it's settled down, and we can get some calm periods for the construction team."

The Hooker Valley Track is open to a viewing platform overlooking Mueller Lake, past the first suspension bridge, while the upper part of the track is closed due to the construction.

Doc recently installed security cameras and warned people to stay away from the building site, after some visitors were seen climbing through barrier fences and gates to access the closed part of the track.

“We can’t wait to re-open the upper part of the Hooker Track and Hooker Hut next year and celebrate the opening of the longest swing bridge in New Zealand,” she said.

Mr Rogers said he would most likely be celebrating with a cup of tea and a lie-down, or a much-needed rest - somewhere calm with no wind blowing.

- Allied Media