It’s not pretty, but it’s sound.
The 48-year old Bruhn Bridge, which carries the Trans-Canada Highway across the Sicamous channel, recently underwent a thorough inspection after a three-foot-long by three-inch-thick piece of concrete broke off the outside deck and fell into a boat travelling below. No one was injured, though the bridge, subsequently, looks as though it was attacked by sledgehammers – which isn’t that far from the truth.
Ed Dodds, the Ministry of Transportation’s area manager of bridges for the Okanagan District, says that once the piece of concrete fell off, a specialized truck was brought in that allowed the maintenance contractor to inspect the entire bridge.
“And we took a chipping hammer and we went over every inch of it, and anything that showed the slightest crack was taken off, removed…,” said Dodds, noting the bridge, because it’s at the bottom of a hill, manages to get a lot of salt on it that gets through the concrete to the rebar.
“The salt gets in and gets to the rebar, and then the rebar rusts and expands and it delaminates the first bit of concrete…,” says Dodds. “It looks ugly in places, but there’s no structural problems at all. Everything is good.”
Exposed portions of rebar were sealed with a zinc paint that Dodds said slows down the rusting while preventing moisture from getting in.
Dodds says he’s able to inspect the Bruhn Bridge every second year and, on his last inspection of the Bruhn Bridge some cracking was noted, but he didn’t see anything that indicated concrete would come off.
“I’ve been doing this for 30 years and I’ve got a pretty good idea of when it advances to that stage, you’ll see rust stains on the concrete, there’s lots of things that indicate it,” says Dodds. “And there was no indication that was going to happen.
“Thank God no one was hurt. But it was just unusual that it happened in that case.”