Corroded connection brought down Algo Mall roof
March 13, 2013
By Canadian Consulting Engineer
Testimony continues at the Elliot Lake inquiry looking into what caused the fatal collapse of a roof over the Algo Mall. Hearings started on March 4 in the northern Ontario town where two women standing in the shopping concourse were killed and...
Testimony continues at the Elliot Lake inquiry looking into what caused the fatal collapse of a roof over the Algo Mall. Hearings started on March 4 in the northern Ontario town where two women standing in the shopping concourse were killed and buried after a roof fell in last June 23. The roof of the mall had been a parking lot.
The latest witness to speak was the building’s original architect, 87-year old James Keywan, who had been retained by Algoma Central Properties to design the mall, which opened in 1980.
On Monday, June 11, Keywan told the inquiry that despite his reservations, the mall’s owner wanted to put parking over the mall because it was the most practical and least expensive option.
According to reports in the Toronto Star, Keyway said it was too difficult to put underground parking in the rock on which the mall was built, and there was no land nearby for parking or a garage tower.
NORR engineers have written a 700-page forensic report for the Ontario Provincial Police on what caused the roof to collapse. It includes photos from a surveillance video that was shot on the fateful day and shows the roof starting to break apart after a car drives over a seam in the roof. The engineers believe the problem was a single steel connector on a column had corroded badly, thanks to years of salt water leaking through the roof. They said the connector was so corroded they were surprised it had held the roof up so long.
On March 8, Dave Monroe, a representative of the U.S. company that had waterproofed the parking lot, admitted that the project had been a problem from the start. A Globe and Mail report said Monroe blamed the roof design, which he said used too many slabs of hollow-core precast concrete loosely tied together, and said “they moved more than we would have expected and in ways we didn’t expect.” The roofing company’s efforts to fix the problem began immediately after the mall was completed.
Both Keywan and the structural engineer of the building, John Kadlec, who testified on March 6, didn’t seem to have attended much to the waterproofing system, nor think it was part of their responsibility. The roof had leaked so badly that people in the town dubbed the mall “Algo Falls.”
Kadlec defended his work on the mall by saying he was “part of a team” and had only visited the site a few times. According to Canadian Press reports, when asked about problems with the waterproofing, he said, “I know nothing about waterproofing … it’s a different profession.”
Professional Engineers of Ontario had revoked Kadlec’s licence in 1994, but reinstated it in 1999. He was not given a certificate of authorization to practice.
Several engineers are appearing as expert witnesses at the inquiry. Dale Kerr, P.Eng. was the first person on the witness stand on March 4. The purpose of the Inquiry is to investigate the events surrounding the collapse of the roof and to make recommendations to prevent such occurrences in the future.
A detailed feature story about the problem-plagued history of the mall was published in Maclean’s March 11, 2013 issue. Click here. http://www2.macleans.ca/2013/03/07/elliot-lake-inquiry-surveillance-footage-pinpoints-exact-cause-of-mall-collapse/