Cracked lighting poles behind MacKay Bridge shutdown

Traffic chaos engulfed Dartmouth and parts of Halifax Monday afternoon as Halifax Harbour Bridges shut down the MacKay bridge to remove four lighting poles.

"We didn't know when they might fall, so it was a matter of urgency," said Steve Proctor, communications manager for Halifax Harbour Bridges.

A 20-metre poletoppled during high winds on Sunday morning, falling across Victoria Road.

"Two vehicles actually ran over the mast because they weren't able to stop in time. Those vehicles were damaged, but nobody was actually hurt," Proctor said.

Engineering inspections showed several more lighting masts with serious fatigue cracks, posing an immediate risk of failure.

Four poles were removed on the weekend, and further tests uncovered four more compromised poles that needed to be removed Monday.

Designed to last 40 years

"All the cracks are in the same location... where the pole is actually welded to the base plate," said Ahsan Chowdhury, Chief Engineer for Halifax Harbour Bridges.

"It's a tall pole, 110 feet tall. And under wind loading it gets a fatigue crack. And then it fails."

Chowdhury says the poles were installed in 2001 by the provincial department of transportation, and became the responsibility of Halifax Harbour Bridges in 2008.

They were last inspected for metal fatigue three years ago.

Chowdhury said the poles were designed to last 40 years, and to withstand windy conditions like those over the weekend.

Chowdhury said the stress cracks were clearly visible on the poles, which is highly unusual.

Replacements coming

"It's so unlikely that you can see a fatigue crack by your eye," he said.

"You need to do a special type of non-destructive testing, called a UT or an MPI. And when you see a crack... by your eye, it means that it's so bad."

Chowdhury says it's not clear why the poles failed prematurely.

Halifax Harbour Bridges is working on ordering replacements, but that will take time.

"It's gonna be a little dark for a while. We will go and we will requisition new poles, but with supply chain issues... it's going to be weeks," Proctor said."We are looking at temporary solutions as required. But right now our focus is on getting the dangerous poles down."

Province alerted

Chowdhury says Halifax Harbour Bridges informed provincial and municipal officials about the cracked polesin case they were installed in other locations in 2001.

"The lights the bridge commission have at the Victoria Road interchange are different from what the Department of Public Works would typically use," said public works spokesperson Deborah Bayer.

"We are not aware of any issues with lights on our roadway network."