If you’ve ever travelled between Wellington city and the airport, you’ve probably been through the Mt Victoria tunnel – and maybe even participated in the symphony of tooting horns that’s long been customary practice. With more than 620m to cover, there’s plenty of time to raise a tune!

Opened in 1931, the tunnel was the first road tunnel in New Zealand to be mechanically ventilated. The technology remains an important feature today, as the tunnel’s now a thoroughfare for about 45,000 vehicles a day, not to mention hundreds of pedestrians and cyclists.

Given the tunnel’s role as a vital part of State Highway 1, it’s important to keep it in top condition.. That’s why BBR Contech is working there right now, strengthening the concrete walls at its entry and exit portals.

The project will anchor the walls in place to reduce the risk of damage or collapse in an earthquake. A complex undertaking given the weak ground conditions at the site, it involves building a concrete beam to link the anchors through the walls, adding steel as extra reinforcing, installing the anchors, and cementing them in place with high-pressure grouting to ensure a firm, long-lasting bond.

Fortunately the work has had minimal impact on those using the tunnel, and thanks to some careful screening the workers are no distraction for drivers. Noise and traffic management plans are also helping to reduce the effects for those in the neighbouring community, while a communication strategy ensures that those directly affected are kept up to date on progress.