Rescue crews should be able to safely sift through the rubble of the collapsed Ontarioshopping mall as they search for survivorsdespite fears of a further collapse, says an engineering expert,if they work slowly and continue to secure the structure as they remove debris.
The search for survivors at Algo Mall in Elliot Lake, Ont. resumed early Tuesdaymorning. Officials had stopped the operation Monday night, citing fears that the structure could collapse at any moment.
A public outcry spurred Premier Dalton McGuinty to order that the search resume. Heavy mining equipment, including cranes and robotics, is expected to arrive in Elliot Lake from Sudbury on Tuesday afternoon.
University of British Columbia civil engineering professor Perry Adebar said Tuesday that while it is very dangerous for rescue crews in the collapsed portion of the mall, they should be able to search for survivors.
“The key thing here to remember is the portion of roof that collapsed is a very small portion of that building, so most of the surrounding building is safe,” Adebar told CTV’s Canada AM from Vancouver.
“The trick is to move in slowly through the safe portions to remove any debris and to support anything that you can in order to move close to the survivor.”
During the collapse, falling debris will have damaged the surrounding structure, Adebar said, making it “very difficult to judge exactly what the capacity of those components are.”
Bill Neadles of the Heavy Urban Search and Rescue Team has told reporters in Elliot Lake that the building "could fall at any time without notice."
Neadles said the integrity of the building has deteriorated since Saturday.
He said a large chunk of concrete has put so much pressure on the wreckage that the mall's support beams are starting to bend. A staircase and an escalator inside the mall have also separated from the rest of the structure.
Adebar said thatas search crews clear debris out of the way, the movement risks bringing down more of the building. The trick, he said, is to “not disturb the damaged structure more than you have to.”
Jim Young, a task force leader with the Vancouver Heavy Urban Search and Rescue, which is similar to the team that is now in Elliot Lake, said crews train “to face all possible contingencies.” These include heavy objects that may be dangling precariously overhead, hazardous materials and dangers of a further collapse.
Crews train to proceed cautiously, he said.
“The rescuers don’t want to become part of the rescue operation, be victims in whatever situation they are facing,” Young told CTV News Channel.
He said engineers determine which areas of the structure are safe, which are considered no-go zones, and which can be made safe by adding support.
“Sometimes buildings just can’t be entered because of the structural instability,” he said.
When asked about how long survivors may safely remain under the rubble, he said it varies from one situation to another.
Generally, though, crews work on the “theory of threes.” A survivor can live three minutes without air, three hours exposed to extreme weather, three days without water, three weeks without food.
