Miami Beach, Champlain Towers South apartment building collapse, Part 16 24

[dik]

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Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[spsalso]

So. From the photo of the cracked area of the planter, it appears the slab, deck, and parts of the planter dropped about one inch. The upper part of the wall on the right did not drop, probably because it was held up by the concrete cap--that being held up as a cantilever from a section that didn't drop.

I am wondering why the top of the column underneath isn't sticking out of the deck an inch. If there was a "buncha" sand between the deck surface and the slab, it could have absorbed the displacement. I suppose.

And all this happened a few days before June 8.

Since the slab and etc. dropped down over the supporting column, there should have been signs of that in the garage. But no one reported such a thing, it appears.


spsalso

 

[Nukeman948]

Thank you my power-pointy hero. At least you understand that the planter box has an East wall and a West wall at this section and that if the box had been positioned so that it's walls straddled the column then we would have likely never seen any damage from the relative motion of the column and slab moving in the vertical plane.

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[Sym P. le]

I have the distinct impression that there is more info available that we are not privy to about the state of decay that was not acted upon. A 1 billion dollar settlement didn't just fall out of the sky either.

This should give folks pause for concern and at the same time relief. Their buildings won't just fall down, however ...

 

[Spartan5]

Is this the sort of damage that could have been caused by a tar buggy that fell sometime prior to the collapse? I kid…

But looking at the planter pictures, imagine if it wasn’t the column under the planter that was punching out. But the column to the left
of that area. Wouldn’t the bending moment in that wall at the planter column cause that long longitudinal crack that is formed there?

Essentially popping the top of the wall up an inch as someone else above postulated. When the vertical joint in the corner of the planter failed, that seems like what the top of the wall would do if it were being subjected to bending restrained by the column beneath.

 

[spsalso]

If I had seen that damaged planter box, I probably would have thought:

"Oh, look. This whole damn building is just falling apart. Sure does need work!"

instead of:

"Oh, look. This building is FALLING APART!!!!!"

That's likely because I see a lot of buildings "falling apart", but very few (if any) "FALLING APART".


So I have some sympathy for someone thinking it was root damage.



spsalso

 

[FJBnomics]

My thinking is the CTS building side of planter column held after initial drop on 87 Park side. Looking at amount of cracks in parking deck west side of planter column indicates the most decayed slab is in parking deck direction. Which points back to pool chemical exhaust in planter at 87 Park perimeter wall.

Column 76 is likely a low point of slab and as such was drain relief point for slab, before planter column failed. I don’t see much rust at column 76, rather I see more white chemically changed concrete. Therefore steel is perhaps only thing prevented punch.

Is planter drop due to slab sag or a shear crack opening up?

Lots of cracks radiating South and west from planter.

Edit1: I concur with Spartan5’s comment and point out this is in line with IanCA’s earlier posts.

Edit2: Live load cycling on deck is a factor and no waterproofing under parking deck

Edit3: Could it be I14.1 that punched first? I believe that was one of IanCA’s theories?

Edit4: How does a delaminated deck affect water drainage and variations between what is happening on top and bottom of slab? Could delaminated deck cause water drainage at column 76, on what was originally a flat deck?

 

[SFCharlie]

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[zebraso]

It looks to me like the long horizontal crack might be more superficial that it appears. As in it might be more lateral movement (maybe from the forces of root growth or the weight of the contents) and there is a shadow being cast to make it look larger. if you project it to the most northern point in the phot there looks to be prior patchwork at the point it emanates from. So this could be the expression of a much older condition. I'm not saying the crack was this pronounced prior to the southern portion dropping. It might have been disguised by the elastomer coating, not needing a patch yet, and just made itself known when the deck dropped. Thoughts?

 

[Sym P. le]

There's no sugar coating that crack


I was thinking along the same lines. The slab didn't need to drop from its perch, braking its back creates some interesting differetials. This also has implications in puddle depth and drainage around a puddles perimeter.

 

[zebraso]

Cetainly within the frame of the closeup. But if you are looking for a reason why the longitudinal strength of the caps was so effective then if the long crack is not the 1/2" plus gap for much further than the corner, then it makes more sense. i.e. there is not 10 feet of wall suspended in air. Or more to the point, there never was. So I/m trying to see if there is another vertical shear back from the corner north, but there is not enough photo detail in the long view. From the long view it look like the crack goes close to zero 3-4 feet from the corner.

 

[FJBnomics]

Could the crack have been in slab under that area, thus having most effect on 87 Park side of Planter column?

 

[Sym P. le]

Seriously, the planter wall has an upper and lower part, the upper part having a greater stiffness than the lower. The lower part moves with the sagging floor while the upper part remains stiff as a beam supported on the column (south) and the slab (north) which we may, for the sake of argument, presume doesn't move much as it is close to the next column to the north. The portion of planter which breaks away south of the planter column (75) sits solely on a portion of slab which is presumed to sag and/or alter it's form due to degradation.

An inch or more of separation is breathtaking but it doesn't defy basic physics.

 

[zebraso]

Seriously..... (drawing)

You're awesome.

 

[FJBnomics]

Just saying cracks could be located where 'Grey' arrows are on the toddler diagram, which is the longer span side of column, thus primarily affecting one side more than the other?

 

[Sym P. le]

yes. next lesson "coloring within the lines"

 

[SFCharlie]

Actually, I like the drawing by Sym P. le (Mechanical) 17 May 22 18:54 better than power pointy...
It's when engineers start sketching on the backs of restaurant placemats that breakthroughs are made...

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[SFCharlie]

Speaking of powerPointy, I was making a very involved slide of the April 2020-June 2021 photo (that I didn't learn much from),
when I started to wonder "why was the April 2020 photo taken?"

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[Reverse_Bias]

We need a 3d drawing cause the planter appears to be leaning east towards the pool also.

 

[zebraso]

why was the April 2020 photo taken?

Unless it was cropped, the subject seems to be "cleanup time". You've got the broom, dust pan, and garbage can. I might have taken that if I had to buy more trash bins and had to make sure I got the model. But seriously, it's a good question. It's a bit bothersome.

Add: anyone look at meta data on these files to see if the cameras are the same camera? Does that get stripped when posting? does png have meta data? It would be interesting if the same person took both (as in the engineer).

 

[Red Corona]

Yes, that planter (in the June '21 pic) has definitely fallen down to the south and east, not just south. Most likely interpretation for me is that the punchout is beginning to happen around column 76 (that's I14.1 right?), not so much around the one under that planter, and it progressed to actual collapse when the effects of that punchout overloaded the one under the planter as well and caused it to punch through too.

Your PowerPoint arrow interpretation looks fair to me, in which case that part of the slab and planter dropped pretty much straight down. The idea that it moved west is probably an illusion of the photo from the other side.

If the collapse did initiate on the deck, and that looks pretty likely with this new information, it's still worrying that the night before there were noises within the building as well. That implies that the whole thing was badly built and in trouble, not just a single flaw - and how many other buildings of a similar age might be like that too?

> why was the April 2020 photo taken?

An interesting question in itself, particularly as it looks like there's already significant deflection there to me.