Residents had reported hearing a loud ‘cracking’ noise throughout the day, which led to a mass evacuation.
A huge crack had been found in a wall, and it was feared the building would collapse.
Engineers estimated that the crack on the 10th floor caused parts of the building to shift up to 2mm.
But this building was not decades old or weathered. It was completed in August this year.
So how does a newly built tower result in an evacuation?
It could be symptomatic of a wider systematic pressure on tradesmen to quickly complete jobs, sacrificing quality over quantity.
A structural engineer who has worked for large developers in the Sydney building boom between 2015 and 2016 has explained the culture on Reddit, breaking down how the problem may have emerged.
“Quite frankly I’m not surprised. I regularly saw poor planning, poor execution, poor workmanship during my limited site inspections, and that’s only the parts I was looking at. Several of the projects I’ve worked on required remedial action during construction due to poor planning and workmanship,” he wrote in the post.
He explained that he was a main engineer for a large building company in the same area, and that the building concepts do not make him confident.
Here is how he explains what might have resulted in Opal Tower.
Firstly, he explains that new connections in the buildings are made without engineer consultation.
“Slab to column and slab to shear wall connections were regularly missed as frequent changes in architectural layouts (to squeeze more apartments in after the initial DA). New connections had to be doweled in – decisions often made by site personnel with no engineering training. Even if an engineer signs off on it there’s rarely checks – they only follow what they’ve been instructed to do in the past,” he wrote.