City of Edmonton officials released details of a preliminary investigation into why girders installed on the 102 Avenue Bridge over Groat Road buckled right after installation earlier in the year.

In mid-March, four steel girders twisted just after they were installed on the new bridge.

The issue set the project back as crews worked to repair the damage and decide what to do next.

On Monday, officials said a mistake made by the subcontractor hired to install the girders led to the twisted metal.

“The investigation indicated the buckling was a result of the subcontractor responsible for installing the girders misinterpreting the precise bracing details and requirements required,” Barry Belcourt with the City of Edmonton said.

At the time, there were concerns that high winds played a role in the incident – Belcourt confirmed the wind was not a factor.

Belcourt said the subcontractor, Supreme Steel, fabricated the girders and designed the plan on how to install them – but the plan wasn’t followed.

“I think that’s the real misinterpretation there, is there probably should have been more permanent bracing instead of temporary,” Belcourt said.

Following the setback, the company removed the girders, repaired them using heat, and installed them successfully.

Now, workers are on an accelerated schedule to have the bridge open by mid-2016.

“Seventeen hours a day minimum, seven days a week,” Belcourt said. “There’s not much more time in there.”

In addition, after September 30, the main contractor Graham Group will start paying more than $11,000 a day in late fees to the City.

Belcourt told CTV News any litigation over the delay has been put on hold.

With files from Nicole Weisberg