(ROB MUNRO / iNFOnews.ca)
July 28, 2021 – 7:00 a.m.
It is not easy to determine what led to the tragic event in Kelowna on July 12th.
That’s the day a tower crane attached to the Brooklyn condominium crashed, killing five people.
“Every crane accident is dangerous,” Yannick Morin, a professional engineer and president of Montreal-based Kraning Inc., told iNFOnews.ca. “None of them are similar. Every accident is completely different. ”
READ MORE: Five men died when a crane collapsed in Kelowna
All possible factors must be taken into account, such as whether the manufacturer’s instructions were followed, when the crane was built, whether there were “mismatched” components, whether safety inspections were followed and other factors.
The problem for Morin and the few others in Canada who are qualified for the job in commenting on the Kelowna collapse is that virtually no information is publicly available.
Many tower cranes in Canada, for example, were built in the 1970s and 1980s with little technology in their operator cabins.
Over the years, they can be modified with “mismatched” tower components. These are considered perfectly legal if designed by a professional engineer and built to these standards.
In the 2000s, construction of a newer generation of cranes with better technology began.
Morin has no information about the age of the tower crane used in Kelowna.
Because of this lack of information, Morin was unable to comment on the possible cause of the Kelowna collapse.
Davis MacGillivray, vice president of Skycrane in Niagara-on-the-Lake, was ready to be a little more direct.
“Tower cranes operate across the country,” said MacGillivray. “They are a safe and efficient way to get involved in high-rise construction. The machines work every day and build thousands of elevators in almost every city. ”
When they collapse, there’s usually a common cause, MacGillivray said.
“These incidents are rare and almost always due to human error during assembly and dismantling.”
READ MORE: Kelowna tower cranes collapse as one of the deadliest in recent history
But it can be too easy to say simple human mistakes, Morin said.
As a professional engineer, he investigated a tower crane collapse in Montreal in 2018. The dismantling took place on a Sunday, so luckily nobody was killed.
“While waiting for the mobile crane to attach the slings, two riggers removed two safety pins,” said Morin. “That was the human factor. But it’s more than human error. It could have been due to a lack of supervision. The manufacturer’s instructions may not be followed. There are many, many questions that the investigation team needs to find answers to in order to find out what the main causes of this accident were. ”
That is the role of the RCMP, WorkSafeBC, and others in dealing with the Kelowna collapse.
“The first thing WorkSafeBC will do is verify that the crew followed the manufacturer’s instructions,” said Morin.
There is also the possibility of structural failure as these cranes can be in service for months or years. But there is also a human factor.
Every morning when crane operators climb their towers, they must visually inspect the structures, Morin said. This means that the logbooks have to be checked by the investigators.
Less frequent inspections of the tower’s exterior surfaces need to be done with cameras and other tech to check things like the welds and for cracks. These inspections also need to be reviewed.
Assembly and disassembly are usually carried out by specialist companies. It is not known if this was the case in Kelowna.
No BC company contacted by iNFOnews.ca commented on any aspect of the accident. They either refused to speak or did not answer.
No one would even speak in general terms that the remaining tower structure was safe enough to remove the body of Brad Zawislak, who was crushed in his neighboring office where he worked.
Such work requires a professional engineer and a team of assistants, Morin said. He knows few such qualified people in Eastern Canada and he does not know the situation in Western Canada.
“First you go into the building and look for the strut of the tower crane,” says Morin. “When you see that the concrete is cracked or stretched, you get the impression that you are not going there. If you feel safe to start dismantling the tower crane, go to the mobile cranes. ”
In the Kelowna case, two mobile cranes were initially used. One secured the top of the damaged tower crane while another held a platform for two workers to unscrew that section. A third mobile crane was added later.
Sometimes it was likely necessary to cut the steel beams where they were bent to prevent the screws from being removed.
The Kelowna crane was safely set down within a week of the first collapse.
It is not always the case.
“In some cases (the safest process) it can literally be evacuating the area and cutting it out from underneath, or attaching a rope and pulling it to the ground so all of the kinetic energy we put into the air as we lift these parts saved can be safely released as long as there are no people in the area, ”said MacGillivray. “That would be the worst-case scenario – evacuate the area, drag the thing to the ground and then clean up the mess.”
Morin noted that tower cranes are not built to “go to the moon”. They are usually an immovable steel structure with a crane swinging at the top.
Mobile cranes, he said, are more like spaceships with a lot more technology. They are much more dangerous as they are not anchored to anything and the operators improvise more.
It is unknown how long the investigation into the Kelowna tragedy will take.
MacGillivray estimates it will take a year to get a coroner’s report on the incident.
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