Constructed of structural steel and reinforced concrete, the Auckland Harbour Bridge is recognized as a national landmark, a tourist attraction and a vital artery, connecting people, places and services via its man-made corridors.
The 1.2-kilometre bridge that spans the Waitemata Harbour connects water, telecommunication, power and gas services to the North Shore and beyond. It is a focus point for many Aucklanders with an average of 180,000 vehicle crossovers daily, and over 64 million a year. During morning peak times, around 200 buses cross the bridge southbound, carrying around 9,000 passengers.
What people often are not aware of is the amount of maintenance that is needed to sustain its daily upkeep. Currently, over 20 Auckland Harbour Bridge Alliance (AHBA) asset management staff work on and around the Auckland Harbour Bridge daily. WSP partnered with Fulton Hogan and TBS Farnsworth in 1998 to create the Total Bridge Services Joint Venture, and in 2012 we became part of the AHBA. Since that time, WSP and its forbearers have continued a tradition of managing large, significant assets while developing innovative tools and solutions to ensure for future-ready infrastructure. Our work for the Auckland Harbour Bridge has led to a number of world-first achievements that bridge the gap between future ready, cost-efficient and environmental civic design.
World First Road Surfacing: In the early 1990s, it was found that there was a lack of a proprietary off-the-shelf road surfacing system that could be used on the bridge. Our team of material specialists, environmental engineers and asset managers identified a possible candidate, which, working with the surfacing supplier, we tested and modified, then developed a road surfacing tailor-made for the conditions and one that met required criteria. This modified surfacing option was applied onto the Auckland Harbour Bridge in 1995. which was the first bridge in the world to apply and utilize this material.
World First Quick Set Repair Material: In 2015 Principal Bridge Engineer and Asset Management Engineer David Ashby, along with the surfacing supplier, modified and developed a quick-set repair material for surface defects. The material was trailed and adapted by the Auckland Harbour Bridge. As a result, the new process has saved time, money and minimized traffic disruption to road users. Its high strength suits the AHBA’s need to provide long-lasting repair at a single application and has reduced the maintenance costs for pot-hole care.
Coatings Management Plan: WSP NZ along with our AHBA partners have developed a Coatings Management Plan for the maintenance of the Auckland Harbour Bridge steel protective coatings. This was undertaken by dividing the bridge into distinct zones, each with its own atmospheric corrosivity, access and containment requirements. Hence, by better understanding the requirements of each of those zones, an optimum maintenance strategy was developed. When combining this strategy with the aim of minimizing the environmental impact of the coating maintenance activities, the most cost-effective lowest whole-of-life solution was identified.
Asset Manager: Auckland Harbour Bridge Alliance
The Alliance currently consists of:
- New Zealand Transport Agency
- Total Bridge Service, which comprises of:
- WSP NZ
- SRG Global (previously TBS Farnsworth)
- Fulton Hogan
Auckland Harbour Bridge gets lit
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 percent 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," Collins says. "This solution encompasses the latest changes in lighting technology, saving over 50 percent in energy consumption and maintaining the NZ Transport Agency’s requirements." 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." 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.