Source: Radio New Zealand
Engineers are trialling containment systems on the land-based areas of the bridge – the structures that will allow workers to eventually access and repaint the bridge. RNZ / Lucy Xia
The Auckland Harbour Bridge repaint project – that’s estimated to take 12 years – has been underway for more than a year, with works beginning at the southern end of the bridge in late 2024.
The New Zealand Transport Agency Waka Kotahi said the original paint coatings on the 66-year-old truss bridge had reached the end of its designed life and needed a full-repaint, which involved stripping down the existing coating and repainting it.
The project, also known as the Truss Bridge Refurbishment Project, was the main contributor that led to the money spent on maintenance and repairs of the bridge increasing from $12.2 million in the 2023/2024 financial year, to $22.4m in the 2024/2025 financial year.
Waka Kotahi couldn’t confirm how much the entire repaint would cost, but said the project has cost $11.6m to date – covering design analysis, strengthening work and the establishment of equipment for the project.
RNZ caught up with the agency’s manager of maintenance and operations for the Auckland and Northern regions, Jacqui Hori-Hoult, to find out the latest progress and challenges with the project.
A year in: Work done at land-based southern end of the bridge
Hori-Hoult said the initial years of the project will focus on repainting the structures underneath the surface road of the bridge.
“When you’re travelling over the bridge, you won’t see a lot, because our project is focused on the refurbishment of underneath the truss bridge, which is under the actual bridge deck,
“So it’s the steel work on the bridge deck which sits in the harshest environment and is also the oldest part of our bridge.”
Hori-Hoult said that part of the bridge is susceptible to corrosion, and the repaint is key to maintaining the structural integrity of the truss bridge.
She said over the past year, work has been mostly around the land-based southern end of the bridge, where sandblasting is used to remove the old coatings before new coatings are applied.
Earlier, an RNZ investigation revealed that NZTA knew that Harbour Bridge maintenance work contaminated homes at Stokes Point/Te Onewa with heavy metals above permitted levels a decade ago, but residents were not told.
Hori-Hoult said the current work has taken precautions to stop any contaminants from the old paint from polluting the environment.
Waka Kotahi: Challenges in repaint of section of bridge crossing sea
Hori-Hoult said expert teams are still working on the plan for how to execute the repainting of the main section of the bridge that crosses the sea, in a way that ensures no potential pollutants get into the sea.
She said they’re hoping to commence work on the sea based section of the bridge at some point in 2026.
The parts of the bridge which have paint containing lead are mostly in one of the spans at the southern end of the bridge, and Waka Kotahi believes that the rest of the bridge is predominantly lead free, she said.
However, Hori-Hoult said they will be using the same environmental protection measures for the main part of the bridge, as they have done for the work at the land-based ends of the bridge, and this would be challenging due it being over the sea.
“So we’re going to have to put temporary work and scaffolding , like we’ve done with the land base with scaffolding,
“Now we have to work through with our experts around how we can manage to attach our containment units in order for us to do a similar type of work, in a very smaller space, but also to make sure whatever we attach is structurally sound for the bridge to enable us to do the work.”
Hori-Hoult said experts were still figuring out what would be the best type of material for the temporary platform.
“We will be installing that full containment system, that you can see when we’re carrying out the [sand] blasting and painting operations, so all materials generated from our operation is actually disposed of to a managed facility that specialises in contaminated material disposal,” she added.
There’s lots of structural elements to think about, for instance how much additional weight can be added to the ageing bridge, she said.
Waka Kotahi said engineers have been assessing the impacts of installing the containment systems on the bridge, and the level of strengthening that is required.
It said teams have been trialling methodologies in the land-based areas.
Bridge to stay grey after repaint
Hori-Hoult said a decision was made to keep the bridge grey as it always has been with the repaint, despite some internal discussions about a new colour for the bridge.
“The Harbour Bridge has been iconic – it’s 66 years old – so you want to keep it as close to its original colour as possible, because of its age and the mana it holds within our city,” she said.
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– Published by EveningReport.nz and AsiaPacificReport.nz, see: MIL OSI in partnership with Radio New Zealand
