Deadly Collapse of the Algo Centre Mall Roof

Deadly Collapse of the Algo Centre Mall Roof

On Saturday, June 23rd 2012, two women were killed and over 20 people were injured when the roof of the Algo Centre Mall in Elliot Lake, Ontario collapsed.

The roof collapsed when one car too many parked on the rooftop parking lot. Investigators say that the car was the final straw to break the unstable roof. Although the roof had been leaking for quite a while, prior inspection failed to detect the concrete and steel corrosion in the structure.

Now, a year later, the town is in a process of rebuilding and trying to bring justice to those who are responsible for the ignorance that caused the collapse.

This roof failure exemplifies the disastrous consequences that can arise from lack of sufficient testing on and care for concrete structures.

So how could this have been prevented? As it turns out, the events leading up to the roof collapse involved people who either chose to ignore the situation or who simply were not knowledgeable enough to be performing the inspections.

Although concrete is a strong and durable material, there are many ways that concrete can deteriorate and the steel inside can corrode. To prevent this deterioration, there must be regular and thorough inspections of concrete structures, and simple visual inspection may not be enough.

Recent advances in concrete testing devices can aid in inspection of concrete structures by testing the concrete electrical resistivity, the rate of steel corrosion and the penetrability of chloride.

All of these factors can contribute to concrete structure deterioration and structural collapse.

Forensic investigators used these products to examine the exact cause of the Algo Centre Mall structural failure. In the Elliot Lake Public Inquiry held on May 30, 2013, in response to the commissioner’s question with respect to advanced non-destructive techniques that engineers can use for corrosion detection, as an expert witness, Dr. Ghods (President of Giatec Scientific of Ottawa) explained that:

“We have a technology at Giatec for measurement of rebar corrosion in concrete. It is a nondestructive technique that allows the corrosion detection from the surface of the concrete. One can first determine if the rebars are corroded or not and if it’s corroded, identify the rate of corrosion of rebar inside the concrete.”

The Algo Mall collapse has taught us that accurate and regular safety inspections of concrete can detect early signs of corrosion and help prevent catastrophic damages and serious injury. The accurate information obtained about the state of concrete structures can help owners schedule their rehabilitation and maintenance operations and prioritize limited funding more efficiently, thereby helping to prevent disasters such as the Argo Centre Mall collapse.

About the author:
Kelsey Hunt is a currently a third year student at the University of Ottawa in Ottawa, Ontario. She is a co-op student working at Giatec Scientific.