What happened to the bridge, when will it be fixed, are we ever getting another harbour crossing – and how long will it take to get home tonight?

Few of us remember a time before the bridge. Its eight glorious lanes run from St Mary’s Bay across the Waitematā harbour to Northcote. Without it Auckland and the North Shore may have remained separated forever, joined only via the Northwestern motorway instead of by an AJ Hackett bungy jump stop.

Now, damage to the bridge threatens our way of life. They’re calling it Carmageddon, an example of how one small act of God can stop up Auckland’s transport arteries. Traffic has slowed through Ponsonby and the CBD as a result of lane closures, affecting even those who never head north.

What’s the damage?

On Friday at 11.10am, a truck from Castles Parcels travelling north was hit by a 127km/h gust of wind, pushing it across two lanes and over the moveable lane barrier, where it became stuck. A truck heading south and carrying a shipping container was blown across at the same time, hitting the bridge’s superstructure.

A steel upright was sheared off and there was damage to the bridge overarch, meaning the centre four lanes were closed off.

Dr Theuns Henning, CEO of Infrastructure Decision Support, told the Science Media Centre the truck crash was “a freak event that could not have been foreseen”.

“The Auckland Harbour Bridge is well maintained and the right protocols are in place for strong winds. The consequences could have been much worse had an efficient infrastructure maintenance plan not been in place,” he said.

When it was completed in 1959, the bridge’s projected life span was 50 years. Industrial pacemakers and prosthetics have kept it going for more than a decade beyond that. It was initially built with four lanes, and in 1969, two “clip-ons” were added to each side. They’ve been plagued with issues since. They’re currently the only lanes available for use.

Waka Kotahi NZ Transport Agency has said the north and southbound clip-on lanes are safe to use as they have their own support structure separate from the central lanes.

Tonight, two lanes will close for repairs; but further work on fixing the damage could take up to five weeks.

How long will it take to get home?

On Saturday, it reportedly took one Devonport dweller six hours to get home from the city. Since then, NZTA has been asking commuters to work from home where possible, but for some it’s not an option. Commuters still battling the bridge this week are saying it’s taking over an hour to reach their homes on the Shore, even with the improvised Western Ring “bull run” in place.

Spinoff staffer and North Shore-dweller Joe Canham said he’s been taking the western route into the city, and timed the commute between his home in Campbell’s Bay and work in Morningside as about an hour. It usually takes him about half an hour going via the bridge. He tried his luck heading north on the bridge yesterday evening, and called it “soul destroying”. “I’ll be taking the west way home tonight,” he said.

Stuff reports that yesterday 11,000 vehicles headed south on the bridge between 6am and 10am, 16,000 fewer than at the same time last week.

What are they doing to the bridge?

NZTA will begin work on a temporary fix tonight, with repairs to the damaged strut taking place from 9pm through to 5am. The lower half of the damaged load-bearing truss will be removed and replaced.

This will allow two lanes from the centre bridge to reopen while work continues on a more permanent solution. Work could continue on Wednesday night.

Closures to enable this include the southbound lanes between Esmonde Road and Hobson Street, the Esmonde Road southbound on-ramp, and the Onewa Road southbound on-ramp.

NZTA’s general manager of transport services, Brett Gliddon, said it was a complex undertaking. “[The replacement] has never been done before so the bridge team must do extensive testing on the bridge before opening it up to live traffic,” he said.

“Once the temporary fix is in place there will be real-life testing with heavy vehicles to ensure it performs to the design specifications and requirements. Only then will a final decision be made about whether the temporary fix is suitable to allow the reopening of additional lanes.”

Permanent repairs are still weeks away from installation.

Do we need a new way to get across the Waitematā?

Auckland Mayor Phil Goff has promised that a second harbour crossing, likely a tunnel under the harbour, will start construction by 2030. Auckland Council will have to find money for this alongside its City Rail Link construction. The tunnel is currently projected to cost about $8 billion.

Professor John Tookey, professor of construction at AUT, told the Science Media Centre the damage showed how dependent Aucklanders have grown on the bridge. “A non-fatal (thankfully) accident on the bridge leads to damage that will impact traffic flows and economic activity for weeks if not months,” he said.

“There is a deep and expanding need to take the pressure off this vital piece of our city infrastructure in order to maintain that idea of being a liveable city for the future.”