A Bridge Built to Last
“When dealing with unsealed steel hollow sections, hot-dip galvanizing is the only way to protect the poles. Galvanizing delivered longevity and was the most cost-effective choice.”
The Auckland Harbour Bridge has been one of the most iconic and busiest bridge structures in New Zealand. It not only connects water, telecommunication, power and gas services; but also carries an average of 180,000 vehicles that travel over the bridge each day. This makes it one of the country’s most vital infrastructure links not only between the North Shore suburbs and the rest of Auckland City, but between the Northland Region and the rest of New Zealand.
WSP led the way in the lighting design and replacement of more than 140 High Pressure Sodium (HPS) lamps with low energy LEDs. The use of LEDs has had an immediate impact, lowering maintenance and operational costs, and significantly reducing light pollution from the bridge. The new lights improve nighttime visibility for drivers and for a safer driving experience.
New hot-dip galvanized poles were designed to withstand the applied loadings and vibrations, while still combining the aesthetics of the original poles. This ensured a visual continuation between the past and the future, while providing a low-maintenance solution for the next 50 years. By hot-dip galvanizing and bolting the poles onto a new welded flanged base connection onto the existing pedestals, our team was able to quickly remove a pole and replace it with a refurbished pole overnight. Galvanizing delivered longevity and was the most cost-effective choice.
An important part of the design process was designing and detailing for durability. It was confirmed that some locations on the bridge were in different atmospheric corrosivity categories. The concern was that the galvanized poles would be too shiny, resulting in reflective sun strike off the poles that may distract motorists. Our team was pleased with the final look, and it had a relatively uniform matte finish.