A strange accident...
On June 23, 2012, the roof of the Algo Shopping Centre in downtown Elliot Lake, Ontario, Canada, collapsed under its own weight. The reinforced concrete slab of the roof, laid out as a parking surface, literally crushed several levels of the mall during the collapse.
Twenty people were injured, and two people unfortunately lost their lives in this tragic accident.
What caused the collapse?
Examination following the accident revealed a failure of the structural steel connexion, supporting the concrete slab, as a result of weakening caused by corrosion.
Fortunately, this type of accident remains rare. Indeed, they are induced by a combination of aggravating factors (water penetration and exposure to oxygen in this case) over areas large enough to lead to an overall loss of stability. Moreover, the safety margin used (when the structure is dimensioned according to the standards in force) gives the structures a better "resilience" and delays the disaster.
Was this type of accident avoidable?
In most cases, this type of failure shows warning signs that can be identified by an expert. These signs usually appear months or even years before an accident occurs: rust flows, moisture stains, cracks or even pieces of unstable concrete. (Increased) monitoring, through visual inspections or non-destructive testing campaigns, would certainly have been sufficient to highlight failures and risks of instability. Faulty parts could therefore have been replaced or repaired in time.
What are the lessons to be learned?
The collapse of the roof of Algo's shopping centre clearly showed the importance of monitoring the health of the structure in order to limit the risk of accidents.
With this in mind, Constru-Care strives to provide inspection and monitoring services adapted to each structure.