Safeguarding our most crucial crossing
Following the collapse of a major bridge in Baltimore, NZTA national manager maintenance and operations Andrew Clark explains measures taken to preserve the resilience of the Auckland Harbour Bridge
The Auckland Harbour Bridge is the most important single transport connection in New Zealand and one of the most travelled routes in the country. In addition to 170,000 vehicle crossings and 35,000 bus passengers daily, the bridge carries two water mains, a high voltage power line, a gas pipe and numerous communication cables.
By 2051, 240 million kilometres of truck movements, 2 billion km of light vehicle movements and 11 per cent of all public transport trips across the Auckland region will rely on this corridor.
The tragic event in Baltimore last month highlights the importance of having a plan in place to prevent incidents like ship strikes, and — in the low likelihood they do occur — to be able to respond to them quickly and effectively.
The risk of a ship strike to the Auckland Harbour Bridge has been assessed as having a rare likelihood due to the amount of risk mitigations in place.
The Port of Auckland and Auckland Transport, through the harbourmaster, have processes in place to mitigate the risk of large ships striking the harbour bridge. These include having a licensed Port of Auckland pilot on board and tugs to guide the ship should it lose power or steerage.
Ships are restricted to moving under the bridge on certain tides and only during daylight hours. For extra guidance, there are GPS identifiers on the bridge’s piers, lights on either side of the bridge alert vessels of hazards, a beacon on the top of the bridge is for aviation and there are channel markers with beacons.
Regular safety inspections and emergency response plans are also in place and tested and maintained with other agencies and local authorities.
Currently, only one cargo ship passes under the Harbour Bridge — the Chelsea sugar ship, which arrives every six weeks. It is much smaller than the container ship that struck the Key Bridge in Baltimore and therefore much less likely to cause such extensive damage.
The bridge piers, built in the 1950s, are massive concrete box-like structures founded on rock beneath the sea bed.
We ensure the piers are regularly inspected, maintained and upgraded when needed to preserve the integrity of the structures.
With Auckland’s population set to hit two million by the end of the decade, we know that an additional harbour connection is a must-have.
Though the bridge is in good condition, it is ageing and vulnerable to closures caused by traffic incidents and adverse weather. That’s why NZ Transport Agency Waka Kotahi is in the final stages of an indicative business case for improving resilience and connectivity across the harbour as part of the Waitematā Harbour Connections project.
This will provide much-needed resilience for the city’s transport network, and presents an opportunity to build a more efficient transport system that supports urban development and intensification, the future of the city’s economy.
Waitematā Harbour Connections is a significant long-term investment in the resilience and efficiency of our land transport system. It will shape the future of the city and has the potential to deliver an impact the whole country will benefit from — ending our reliance on a safe but single connection.