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Doomed Mall: 1 Second, 1 Car

Monday, March 18, 2013

More items for Program/Project Management

With a weld ravaged by water and corrosion, it took just one car—in one second—to cave in an Ontario shopping mall last summer, trapping and killing people inside, engineers studying the accident have concluded.

“The trigger of the collapse on June 23rd, 2012, is quite evident,” concludes a 700-page report from NORR, a global engineering firm that conducted a forensic investigation into the disaster for the Ontario Provincial Police. “The evidence of this is overwhelming.”

The report was introduced Wednesday (March 13) at The Elliot Lake Inquiry, a public hearing into the collapse of the Algo Centre Mall in Elliot Lake.

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A makeshift memorial in June honored victims of the Algo Centre Mall collapse.

The cave-in killed Lucie Aylwin, 37, and Doloris Perizzolo, 74, and injured two dozen other people.

The hearing, which opened March 4, adjourned Thursday (March 14) to give the commissioners and other parties time to read the voluminous new engineering report, which will become a key piece of evidence in the investigation.

The adjournment temporarily suspended the testimony of Rod Caughill, former Development Supervisor for Algoma Central Properties, the mall's original owners. Caughill is expected to resume his testimony Tuesday (March 19).

Lifelong Maintenance Issue

Earlier Wednesday, Caughill told the commission that the original owners knew that the unsheltered rooftop parking structure would present problems. Substantial evidence and testimony has documented that the structure leaked seriously from the time it opened.

"We thought the roof would be a maintenance issue for the longevity of building," Caughill testified.

Previous testimony by the mall's initial waterproofing contractor has detailed severe leaking problems at the structure and the company's futile attempts to mitigate them.

Photos: Elliot Lake Commission

Leaking caused considerable damage to the mall's library branch. Librarians complained of "water dripping down their necks" in the stacks, "buckets everywhere and plastic sheets having to be placed over the stacks."

Contractor Dave Monroe, formerly of Harry S. Peterson Co., said the mall's original owner had opted for a partial waterproofing approach to save money, using a system that Peterson had never tried in such an application.

Fix Rejected

Caughill testified that the leaking eventually made cement patching, joint repairs and roof drainage daily maintenance chores. By 1990, the owners hired Trow Engineering Limited to evaluate the problem.

Trow's report, released in 1991, outlined multiple problems, including debonding of three expansion joints from roof deck concrete coreslabs they were holding together. Trow also concluded that the structure could not be made watertight.

The Trow report warned that steel beam corrosion would accelerate rapidly if the leaking was not resolved. The firm recommended waterproofing the entire deck, either over the old waterproofing or after removing the old waterproofing. But the owners declined.

Mall owners rejected an engineering firm's waterproofing recommendations, because "we didn't have any faith in the whole concept of what they were proposing," testified development supervisor Rod Caughill.

"We didn't have any faith in the whole concept of what they were proposing," Caughill testified. "They raised more questions than they answered."

Caughill also said that the owners thought the deck could not bear the weight of the waterproofing proposed.

"Unfortunately, despite our efforts, the mall never became watertight during the period we owned it," he said.

New Engineering Report

Other evidence has attested to crooked columns, missing bolts and corroded steel in the structure even before it opened in 1980.

Structural engineer John Kadlec, who signed off on the project at the time, testified earlier that he had known of the problems and called the workmanship shoddy. Kadlec said, however, that reports at the time showed the problems had been corrected.

The newly released NORR report follows a draft report that the architectural, engineering and planning firm completed in November. Multiple news reports indicate that the final version echoes the draft's conclusions.

Video stills from a new engineering report show the moment of the roof deck's cave-in. The vehicle cleared the failed section just as it gave way.

Investigative reporter Michael Friscolanti, of Macleans, who has written a book on the accident and reviewed the full-length report, said the document lays the blame on water damage that had corroded a weld on a steel connector that held up the slabs.

"[T]he main culprit was a rusty steel beam that ran directly above the mall’s second-floor lottery kiosk, ground zero for the eventual collapse," reported Friscolanti.

Failed Weld

“The collapse was initiated when the welded connection between the angles and the column flange failed,” the NORR report says. “By the day of the collapse, the welded connection had been so heavily depleted over years of corrosion that the passing car was the last straw that the connections could take.”

When a Ford Explorer crossed the section, it caved in just as the car cleared.

“The nature of the failure was sudden,” the report says, “and the duration of the collapse lasted only one second.”

Video of Wednesday's testimony is available here. In addition, a testimony transcript is available here.

Comment from Anna Jolly, (3/18/2013, 10:07 AM)

These kinds of deaths are so senseless. They are all about shoddy workmanship and cutting corners. Terrible thing.

Comment from Jim Johnson, (3/18/2013, 11:39 AM)

The questions in my mind are Why didn't they shut down the rooftop for parking? and If they knew there were corrosion problems with the supports why did they not reinforce them? Perhaps they could not stop the leaking, but they could have stopped the collapse.

Comment from Tom Schwerdt, (3/19/2013, 9:19 AM)

I suspect they only could have postponed the collapse - if a single car was the trigger, how much longer until it came apart on its own? From the story, it sounds like the proposed solution was given 20+ years ago - seal the entire deck. The owners declined to do so and allowed the continued moisture (and presumably salt) intrusion.

Comment from M. Halliwell, (3/19/2013, 10:31 AM)

Jim, I would suspect that the motivation to keep the parking lot open was probably a lack of parking in the surrounding area....close the parking lot on the roof and you seriously cut the business in the mall (which the owner and tenants would likely have opposed). I agree with Tom....it sounds like it may have been a brilliant idea to save space by putting the parking on the roof, but the way it was done and how it was managed since set the stage for this tragic failure. Sometimes it's the design (and I've seen some doozies), sometimes it is the execution (my professors in University brow beat us with one particular example), but when combined with a lack of desire or motivation to fix it afterwards, the result is a failure of some sort. It is tragic that it was a fatal failure in this case.

Comment from Jim Johnson, (3/20/2013, 1:53 PM)

This is a pretty open and closed case. Both the previous and current owners chose profits over a life. Being a strong believer in personal responsibility I think the individuals should be criminally charged with at least manslaughter. They knew the roof was leaking and it could not be stopped, they were informed the leaking was causing corrosion of the steel and even a Walmart greeter knows steel will only corrode so much and it will fail. In each case there were other options available, but both owning parties, previous and current, chose profits over life.