New pictures reveal a central strut on the Auckland Harbour Bridge bent out of shape and twisted after Friday's truck crash.
Strong winds lashed the City of Sails on Friday, toppling a medium-sized truck heading northbound on the Auckland Harbour Bridge and blowing a southbound truck onto a tilt.
The southbound vehicle hit the bridge's structure but was able to right itself and carry on.
But it left damage to a steel strut which has forced four lanes on the bridge to be closed while repairs occur.
New photos released by the New Zealand Transport Agency on Saturday night show the bolted steel strut "bent out of shape" and twisted in the centre. At the bottom, bolts have been broken away.
"The upright strut is fixed to the bridge top and bottom with a series of bolts. These bolts have sheared off and left the strut detached at the bottom. The strut is bent and twisted at the point it was hit," says NZTA senior journey manager Neil Walker.
The strut helps support the bridge's weight and while the structure isn't going to collapse, NZTA says cars shouldn't be driving down the central lanes.
Engineers are now currently assessing how to repair or replace the strut, while also checking to see if there is damage elsewhere. The sheared end of the damaged strut has been temporarily bolted back on to the bridge.
NZTA general manager transport services Brett Gliddon said on Saturday that a permanent solution could be more than five weeks away. A temporary solution could be found by engineers this weekend, but there's no guarantee of that and it may take a week to implement.
Gliddon described the strut as a "pretty big piece of metal". Because each part of the bridge is unique, he said it isn't feasible to have a spare replacement for each piece.
"It goes from the road level of the bridge right up to the top of the bridge. It is pretty big in diameter, so it would be 400 or 500mm square and it is obviously bolted at the bottom with a big steel plate and bolted at the top. We have got 15-20 bolts holding it in place.
"We haven't had a structure on the bridge hit like this before."
The NZTA says that while motorists may not be able to see repair work being conducted on the bridge, they can rest assured the agency is doing everything it can to get the lanes back open and that much of the work is happening offsite.
Two lanes northbound and two lanes southbound on the bridge's clip-ons remain open, but traffic was horrific for motorists on Saturday.
Those wanting to head into the city or north are being asked to consider using the Western Ring Route or to work from home if possible. Public transport is also available and Auckland Transport is looking at capacity.
With 170,000 vehicles crossing the bridge each weekday, NZTA says it understands the "economic significance of the Auckland Harbour Bridge to help support the movement of people and freight within the region and throughout the rest of New Zealand".
Gliddon said NZTA has been working on a possible second harbour crossing and that Friday's incident showed the need to have capacity on the network when events like these occur.
The National Party announced in July that it wanted to see work start on a second crossing in 2028. It believes that would take the form of a road and rail tunnel under the harbour.
"As Auckland wakes up to the fact that the middle four lanes of the harbour bridge could close for an extended period due to yesterday's accident, just shows that Auckland needs National's plan to build a new second harbour crossing over the Waitemata sooner rather than later," National's Judith Collins said.
The Transport Minister, Labour's Phil Twyford, told Newshub he acknowledges the frustration the delays have caused motorists and that there's "no doubt that Auckland will need a second harbour crossing". Planning is underway.
"Even if you started tomorrow on a second crossing, it will still take about a decade, so it's not a quick fix," he said.
"You can't rush the planning of it as no-one wants a repeat of the first harbour bridge where it needed extra capacity by the time it was finished."
Julie Anne Genter, the Green Party transport spokesperson, said the party has long campaigned for rail to Auckland's North Shore as well as a "comprehensive rapid transit network around the city".
"Rail to the North Shore will make it easier for people to leave the car at home and get around the city, and it would free up space on the Auckland Harbour Bridge for people and goods that need to travel by road."