Auckland Harbour Bridge: Good weather overnight fast tracks permanent fix

Perfect weather conditions in Auckland overnight has helped to fast track work to fix the city's harbour bridge - albeit temporarily.

The lower half of the strut that was damaged when a truck hit it last Friday - after being tipped over by a strong gust - has been replaced with a section of freshly fabricated steel.

The temporary fix comes after efforts by specialist bridge engineers and fabricators to assess the damage, design the new strut, calculate and plan the repair as well as manufacture the strut itself.

Waka Kotahi NZ Transport Agency said in a statement: "We had perfect weather conditions on the harbour bridge overnight and so progress was much faster than we had hoped.

"There was very little wind, good temperatures and visibility - which meant the team were able to get the new section installed and carry out the testing all in one night."

The overnight fix has resulted in three lanes being opened to traffic coming from either side of the bridge from early this morning.

NZTA said although that was hugely positive for the public, it was important to note that the bridge is still in a "compromised state".

The crew working on the Auckland Harbour Bridge overnight. Photo / Waka Kotahi NZTA

Because of that, loads on the bridge will need to be managed carefully.

"This will remain until the permanent solution is in place and the bridge can support its full weight capacity again."

Testing carried out using heavy vehicles before bridge reopened

The crew involved in the overnight work carried out real-life tests to ensure the bridge was performing the necessary design specifications and requirements, NZTA said.

Heavy vehicles were brought in for that testing.

However, no overweight vehicles are allowed across the bridge at the moment - and they are being asked to stay away until the permanent fixture is installed.

A strut is temporarily fixed on the harbour bridge overnight. Photo / NZTA

Work is now moving towards a permanent repair in order to reopen the bridge entirely. But NZTA warned that that could still be "weeks away" from installation.

The bulk of that permanent solution involved the calculation and peer review of the new permanent strut in relation to how it will impact on the performance of the whole bridge.

"This includes careful calculations on how to re-balance its load-bearing function.

"The new modelling is necessary because the materials of the new structure will not exactly match those that were installed 60 years ago."