Vancouver B.C. Rooftop Parking Collapse 1

[Sym P. le]

CTV News - 2 in hospital after rooftop parking lot in East Vancouver collapse
CBC News - 2 taken to hospital after rooftop parking deck collapses into office in East Vancouver

When I heard the news on the radio earlier today, that a rooftop parking structure in East Vancouver collapsed, my mind immediately went back to an incident in the mid 1990's when a loaded concrete truck punched through an elevated structure, landing on it's ass end in the business below, knocking the driver unconscious. It turns out to be the neighbouring address, however, everything about the development screams that it's the same owner development.

The earlier incident occured in part because the height limitation frame at the parking entrance had been removed to facilitate renovations. The concrete truck driver didn't get the message. I notice in Google Street View there is no equivalent warning structure at the entrance to the 3438 address. WorkSafeBC better be all over this.

Google Earth view of 3434/3438 Lougheed Hwy., Vancouver, B.C.

3434 Lougheed Hwy. - Site of Today's Incident

3438 Lougheed Hwy. - Site of Mid 1990's Incident

 

[dold]

The uniform load of a vehicle is applied to spots with a contact pressure approximately equal to the tire pressure. You can pass the uniform load criteria and badly fail the contact pressure requirement. The result - either immediately or after a while can be in punch through failures.

My understanding of the 40psf uniform, 2000lb point load on 4"x4" patch is to simulate a car jack, not the tire contact patch. But I suppose the tire contact patch would be roughly the same size and force. Seems less likely though that a tire would punch as easily as a jack.

 

[Lomarandil]

Tire contact area is somewhat higher -- 10"x20" for a design semi-truck, maybe as low as 4"x6" for a passenger vehicle.

2000lbf over 4"x4" (the jack load) is 125 psi, and nobody runs automobile tires inflated that high.

But yes, loaded forklifts (or wheel loaders) are a totally different animal and require additional consideration.

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just call me Lo.