An innovative new system, designed by WSP NZ, is lighting the way for users of the Auckland Harbour Bridge.
It has seen more than 140 High Pressure Sodium (HPS) lamps replaced with low energy Light-Emitting Diodes (LEDs).
The solution has had an immediate impact, delivering over 50% power savings, lowering future maintenance costs and significantly reducing light pollution from the bridge.
Crucially, the new lights improve night time visibility for drivers and are more effective in the rain, making for a safer driving experience.
For those involved, the eight-year project has been a massive undertaking.
Andy Collins, WSP Technical Principal – Lighting Design, says there was a very real need for the upgrade and involved multiple engineering disciplines.
“LEDs are more robust than the old luminaires, which themselves have been replaced a number of times over the decades. This solution encompasses the latest changes in lighting technology saving over 50% in energy consumption and maintaining the NZ Transport Agency’s requirements,” he says.
Collins adds that the reduced visual impact from the LEDs also benefits the regular Vector Lights displays – which are also driven by thousands of LEDs attached to the bridge structure.
The project grew in complexity when taking into account the fatigue issues associated with the ageing lighting poles.
Raed El Sarraf, Technical Principal – Materials and Corrosion, says the upgrade required the design of new poles, as the original poles were reaching the end of fatigue life due to vibration from the bridge traffic and wind loading.
“Fatigue has been a concern for the past decade resulting in the annual inspections and monitoring to detect cracks at high stress locations on the poles. All of which adds to the operating cost of the poles,” he says.
El Sarraf says the new hot dip galvanized poles have been designed to withstand the applied loadings and vibrations, while combining the aesthetics of the original 1959 and 1969 poles. This ensures a visual continuation between the past and the future, while providing a low maintenance durable solution for the next 50 years.
All up, 118 poles were installed by Total Bridge Services and delivered by the Auckland Harbour Bridge Alliance.