Parking Garage Concrete Column Failure - Ontario Canada 1

dold said:

Doesn't look great, but better than being a main building column.

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Looks like a progressive collapse that has already started, but the progression is slow. The Reddit poster says that the parking extends under the small tower. Champlain Towers South, by one of the popular interpretations of the collapse sequence, came down from something not that different.

And yet, people are still parking their cars in that parking structure, eh? (sorry, I couldn't help myself).

John R. Baker, P.E. (ret)
Irvine, CA
Siemens PLM:

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It's not clear - but this may be a post-tensioned floor system.

These ramp columns have smaller lengths between slabs - and thus are substantially stiffer than conventional building column. This cracking may be a result of the stiffness of the column restricting the pre-compression but the column not being designed for that shear load. As a rule of thumb - we increase the provided shear reinforcement for these types of columns on a pt-slab garage.

I don't know why the cracking at the bottom, but the top appears to be shear on a very short column (lateral support provided by the soil retention). Exposed... could be thermal issues, but I don't know how cold it gets in Niagara Falls.

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So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

The garage is stepped to follow the grade of the property.


Google Maps (link)

Very short columns are prone to that sort of cracking due to thermal movement. Not expansion, but rather contraction and restraint.

dik said:

I don't know how cold it gets in Niagara Falls

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Pretty cold. It's just north of Buffalo, which got absolutely buried this past winter. We sent our plow crews there to help them dig out.

I'm at the same latitude on the other side of the state. They probably range from < -10F/-23C in winter to > 90F/32C in summer. Outside the mountains, winter frost depth for upstate NY is generally taken to be about 4 ft/1.2m.



My glass has a v/c ratio of 0.5

Maybe the tyranny of Murphy is the penalty for hubris. -

So...this came from a reddit post...has anyone reported this to the authorities for investigation and correction?

Never mind - I see the note in the OP now. I missed the "open eyes" step in my reading procedure...

From the OP for this topic:

"The OP [from another post elsewhere] has reported this to the building department and they are aware of the 'issue'".

Seems to me that the "issue" is that the structure might fail at any moment. What's holding it up?

Would this problem not have arisen if the designer had placed an expansion joint between the middle deck and its support on this column? This would have eliminated lateral forces from that deck. I think. There appears to be enough column under the middle deck to have done the job, without tying that deck to the part of the column that supports the other two decks.

A brief electrical note: There is a piece of conduit that runs down the column and then turns and goes under the middle deck. There is a one-hole strap that formerly held the conduit onto the column. It appears the middle deck has moved laterally far enough to draw the conduit from inside the one-hole strap--about one half inch. Very impressive, in a special way.


spsalso

VERY roughly, I get a thermal expansion of the middle deck of .33 inch, between temperature extremes. Assuming the top and bottom deck expand about the same, then the middle of the column would be deflected by .33 inch.

spsalso

Could it be that an extended cold spell chilled the foundations.
Then a very hot sunny day,heated the slab that then expanded differentially to the foundations?

--------------------
Ohm's law
Not just a good idea;
It's the LAW!

Not sure if this could be an issue, but the in situ bedrock in this area is highly compressed. It heaves elastically when excavated then creeps significantly once the structure is built. There’s also expansive shale in the area.

This cracking may be a result of the stiffness of the column restricting the pre-compression but the column not being designed for that shear load.

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Looking at the direction of the shear crack, it looks the opposite direction to what I'd expect from the scenario you are suggesting with a pt system - more in line with expansion/some other lateral force "pushing" into the column from the middle slab, rather than "pulling" away.

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Why yes, I do in fact have no idea what I'm talking about