Flat Slab Collapse in Windsor, Ontario, Canada
Flat Slab Collapse in Windsor, Ontario, Canada
(OP)
http:/ /www.winds orstar.com /accounted +officials +next+door +apartment s+evacuate d/3250783/ story.html
Thankfully no one was seriously hurt. Every time i see one of these, I'm always shocked at how dramatic the punching shear failure is.
No word yet on cause, although that boom lift is suspect.
Thankfully no one was seriously hurt. Every time i see one of these, I'm always shocked at how dramatic the punching shear failure is.
No word yet on cause, although that boom lift is suspect.






RE: Flat Slab Collapse in Windsor, Ontario, Canada
There wasn't much spare capacity there, collapse would have happened anyway, sooner or later.
Rebar corrosion would have to be a suspect.
RE: Flat Slab Collapse in Windsor, Ontario, Canada
I've parked on that structure several times (my favorite thai restaurant is out front). I've never thought that the workmanship of the concrete looked very good. Should be interesting to see how this one turns out.
RE: Flat Slab Collapse in Windsor, Ontario, Canada
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RE: Flat Slab Collapse in Windsor, Ontario, Canada
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RE: Flat Slab Collapse in Windsor, Ontario, Canada
Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask
RE: Flat Slab Collapse in Windsor, Ontario, Canada
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Doug Jenkins
Interactive Design Services
http://newtonexcelbach.wordpress.com/
RE: Flat Slab Collapse in Windsor, Ontario, Canada
RE: Flat Slab Collapse in Windsor, Ontario, Canada
I thought it didn't look quite right, but with the yellow painted columns and Canadian location I thought it must be the same one.
Doug Jenkins
Interactive Design Services
http://newtonexcelbach.wordpress.com/
RE: Flat Slab Collapse in Windsor, Ontario, Canada
RE: Flat Slab Collapse in Windsor, Ontario, Canada
Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask
RE: Flat Slab Collapse in Windsor, Ontario, Canada
RE: Flat Slab Collapse in Windsor, Ontario, Canada
asixth, you are probably speaking of Dr's. Dilger and Ghali out of the University of Alberta, they developed stud rails back in the 80s, and since they have been marketed throughout the world. They also developed the code equations used in the canadian concrete code for punching shear reinforcement.
the canadian code is actually pretty far along compared to ACI when it comes to punching shear, due to Dilger and Ghali's research being accepted there first. Although being built in 1948, this one obviously predates that..
RE: Flat Slab Collapse in Windsor, Ontario, Canada
Dik
RE: Flat Slab Collapse in Windsor, Ontario, Canada
RE: Flat Slab Collapse in Windsor, Ontario, Canada
In the 1948 structure which failed, a lot of things could have contributed, including overloading, poor concrete, poor construction practice, deterioration due to salting, the list goes on. This appears to be a flat plate, and in 1948 I think this type floor was uncommon and perhaps ill understood by some. Flat plates in the early days were primarily used in lift slab construction.
RE: Flat Slab Collapse in Windsor, Ontario, Canada
And now we've skinnied it down to 40 psf. A few inches of asphalt overlay and most of that's used up.
RE: Flat Slab Collapse in Windsor, Ontario, Canada
Dik
RE: Flat Slab Collapse in Windsor, Ontario, Canada
RE: Flat Slab Collapse in Windsor, Ontario, Canada
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RE: Flat Slab Collapse in Windsor, Ontario, Canada
My belief is that 22kip (100kN) crane (whether it was loaded to 100kN or not is another question) is the 'straw which broke the camel's back' and that an engineer should have been consulted prior to putting that crane on the floor. No competent engineer would have certified that floor to be structurally adequate to support that load. The deck looks 5-6" with not much reinforcement. Assuming any structural plans of the carpark would be long gone by now.
RE: Flat Slab Collapse in Windsor, Ontario, Canada
RE: Flat Slab Collapse in Windsor, Ontario, Canada
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A lot of factors seems to be adding up here, for the perfect storm so to speak. Extra asphalt, boom truck, rebar corrosion, shotty construction. It's pretty amazing when you think how much it takes to overcome the safety factors.
RE: Flat Slab Collapse in Windsor, Ontario, Canada
The "Lets install a protective layer layer of asphalt to protect the corroding rebar" scenario.
Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask
RE: Flat Slab Collapse in Windsor, Ontario, Canada
Dik