Braid: Concrete pipe that turns to powder — the real problem with the Bearspaw water line?

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City hall is giving us precious little information about what went wrong on the Bearspaw South Feeder water line.

We hear that reinforcing steel wires snapped or weakened — in six places — and there may be more.

That’s about it for disclosure.

But the city — which says a full investigation of the problem will follow — has known trouble lay ahead since Jan. 26, 2004, when a smaller main popped on McKnight Boulevard.

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Other lines of the same type — including the giant feeder — were instantly understood to be vulnerable to similar “catastrophic” failure.

The area was flooded in frigid weather. A hundred thousand residents were without water.

“That was when we found out we had a serious problem,” says James Buker, who was the city’s head of water transmission and distribution for most of 42 years before his retirement in 2016.

Buker and everyone else had a shock when they dug down to the pipe.

“Under McKnight Boulevard that pipe, that concrete, was talcum powder,” he says. “It had deteriorated that bad.

“That pipe was only 20 years old, and we thought, all this concrete pipe we put in should really be fine if the sulfide resistance was what we asked for.

“It should have been bulletproof. But it failed.”

The problem wasn’t steel reinforcing wire. It was the concrete that blankets the wire and was supposed to be invulnerable to chemical attack and corrosion.

But the concrete broke down, exposing the wire, which snapped.

James Buker, a retired city waterworks employee, was on scene in 1975 for the installation of the pipe that burst in Montgomery on Wednesday night. He returned to the location for a photo on Friday, June 7, 2024. Darren Makowichuk/Postmedia

City hall went on high alert back in 2004. A whole new section was created to monitor water pipes. Rigorous inspections were done, but probably not on the Bearspaw feeder because it’s always full and remote robots can’t function in water.

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“I put all the pipe in from 1975 to 2016, and the only time we had failure is when the concrete deteriorated because of chemical attack of sulfides and chlorides. We’ve never had a failure that you could say was just steel wires,” he says.

“Concrete cylinder pipe made from 1955 to 1990 was probably deficient. It was more porous, meaning it could be attacked by chemicals.

“In 1990 this was tightened up and we haven’t had a failure of a pipeline built since then.”

Water main break

Another water system in Calgary has never failed — the Glenmore reservoir line, installed in 1932, when the population was only 85,000.

In 92 years, there hasn’t been a major problem.

Calgary had dirty, cloudy drinking water back then. The Glenmore project was a massive upgrade and the biggest capital project in the city’s history.

It earned international praise for the construction and the method of pouring concrete directly on site.

“You’d have to take a diamond cutter to go through that concrete, it’s so hard,” says Buker.

The American Water Works Association, still a key body in the pipe business, wrote a report in 1934 full of praise for Calgary’s ingenuity and beauty, quoted as, “The city is indeed picturesque, with its distant view of the Rockies to the West.”

Like everyone involved when the Bearspaw Feeder line was installed, Buker had no idea they were using concrete pipe with a shorter lifespan than that used four decades earlier.

Pipe that can — quite possibly and for years to come — turn to talcum powder.

Don Braid’s column appears regularly in the Herald

X: @DonBraid

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