Miami Beach, Champlain Towers South apartment building collapse, Part 06 131

[SFCharlie]

A continuation of our discussion of this failure. Best to read the other threads first to avoid rehashing things already discussed.
Miami Beach, Champlain Towers South apartment building collapse
Miami Beach, Champlain Towers South apartment building collapse, Part 02
Miami Beach, Champlain Towers South apartment building collapse, Part 03
Miami Beach, Champlain Towers South apartment building collapse, Part 04
Miami Beach, Champlain Towers South apartment building collapse, Part 05

SF Charlie
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[Js5180]

Spartan,

I think there’s a flaw in your theory but I may not be fully understanding the timeline you have in mind.

Two issues:

First, prior to the pool deck collapse, there should not be ANY weight distribution going on, if the pool deck was the trigger. So the prior day’s noise complaints from 1211 still need an explanation.

Second, between the pool deck collapse and the main collapse, what type of weight distribution could be going on above, that was not also causing problems in 111? If the shape of 111 was compromised or otherwise wasn’t holding its weight, wouldn’t we have heard instead that the floor was buckling, or the windows were cracking, or something like that? How would 111 be intact, while floors way above it are actively shifting onto different columns?

I’m struggling with how a pool deck collapse could cause remote weight shifting without much more obvious issues nearby, at all times during the collapse. After all, the final collapse wasn’t upper floors moving around, but lower floors giving out.

 

[Spartan5]

Not me too? I said they didn’t hear it. As in it didn’t happen.

 

[Spartan5]

So the prior day’s noise complaints from 1211 still need an explanation.

Coincidence? Older people hear things and don’t sleep well? (I know, ageist, but it happens to me too).

What people in any of the upper floors didn’t hear, or report to have heard, or escaped because they heard; was any part of the building’s upper levels collapsing. Why not?

 

[Spartan5]

Second, between the pool deck collapse and the main collapse, what type of weight distribution could be going on above, that was not also causing problems in 111? If the shape of 111 was compromised or otherwise wasn’t holding its weight, wouldn’t we have heard instead that the floor was buckling, or the windows were cracking, or something like that? How would 111 be intact, while floors way above it are actively shifting onto different columns?

Theres not much “between the pool deck collapse and main collapse.” 111 heard the noises. Went to complain. And then got the hell out of dodge.

The progressive collapse of the slab built slowly built to a crescendo as more and more gave up over several minutes, maybe longer. That was what I was describing. It wasn’t until that progressed to the point that it impacted the building columns that things got grave.

The yielding of the columns, gross distortion, and subsequent final collapse of the building took place over a minute at most probably. 111 was on their way out of the lobby at that point.

 

[gonefishing2]

I was not implying any sinister. The plates on the post anchors are like 14-16” square. Those PH columns are small. Holes for plates are at outer edge of plate. So if plate centered over column, then holes drilled are near edge of column. In the collapsed patio deck, there appears to have been rebars near edge of column. If PH roof same scenario, anchor drilling for centered plate might get rebars near or at column edge providing either negative moment or some shear support? They were to scan concrete before drilling. Maybe they did or did not??

 

[bones206]

I just want to confirm some logic:

The people who came up the garage elevator into the lobby and walked into a cloud of dust and noise, they witnessed the collapsed slab and sunken cars in the exterior surface parking area adjacent to the lobby, correct? As far as I know, they did not state that they witnessed any collapse inside the garage before stepping into the elevator (besides hearing some weird noises). So the logic I am inferring from this sequence is that the collapse in the garage documented by the tik tok video could not have PRECEEDED the collapse of the surface parking area near the lobby, or they certainly would have noticed it before getting on the elevator. The tik tok area collapse must have either been at the same time or subsequent to the surface parking area collapse.

I feel like this distinction is important when thinking about what part of the plaza slab may have failed first. But is this logic sound or is there a flaw I am missing here?

 

[w-streng]

I quoted warrenslo, not you! Sorry for the confusion.

Yes, I am uncomfortable with the PH support too. These edges (and others) are not comforting at all.

 

[gonefishing2]

w-streng, Agree. It is like because PH roof only 6” slab, they put columns at outer edge of cantilever to let 12th floor cantilever handle PH cantilever and double parapet walls in that area. PH bootleg addition

 

[CE3527]

Just from a logic standpoint about the roof/ac theory, what seems to be getting suggested is that the roof structure was so incredibly flawed that a few holes in a column or some 100lb rolls of roof material caused it to collapse, but that the 12th floor structure was so incredibly strong that it withstood the massive impact of the falling penthouse roof slab.

 

[gonefishing2]

And as I remember PH cantilever roof projected out further into space than 12 floor cantilever and parapet.

 

[Seppe]

Just from a logic standpoint about the roof/ac theory, what seems to be getting suggested is that the roof structure was so incredibly flawed that a few holes in a column or some 100lb rolls of roof material caused it to collapse, but that the 12th floor structure was so incredibly strong that it withstood the massive impact of the falling penthouse roof slab.

I'm not sure "suggested" is the right word as much as it is "assured" by some posters when it comes to those defenders of the "roof-first" theory. And their theory is that big chunks of roof/penthouse fell (apparently with a convenient delay from when the culprit roof anchors themselves were actually installed), and spectacularly blasted through the pool deck slab like a kill-shot.

 

[arbitraria]

The plates on the post anchors are like 14-16” square. Those PH columns are small. Holes for plates are at outer edge of plate. So if plate centered over column, then holes drilled are near edge of column.

That would certainly explain this photo posted a few days ago...could have missed the column completely.

 

[Penagwin]

The roofing repair permit was released titled "8777 COLLINS AVE PERMIT # 21-211-APPLICATION" from

https://surfside.one/public-records-search/

I'm not sure if it's interesting or not, it cost them 1.3mil

 

[Santos81]

That would certainly explain this photo posted a few days ago...could have missed the column completely.

I’m not uncertain that’s part of a Rooftop Equipment Hurricane Stand or the machine room stairs, not a posted fall arrest anchor.

 

[SFCharlie]

...no longer live, but I started watching over again from the beginning, I may be confused, but it looks to me like they are excavation below the garage floor?
Watch Live: Champlain Towers South Recovery - July 15

SF Charlie
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[zebraso]

I feel like this distinction is important when thinking about what part of the plaza slab may have failed first. But is this logic sound or is there a flaw I am missing here?

Sounds pretty logical to me. These people are key witnesses to the progression. Unlike nest, they can describe what was going on around them at the time. If they can recall accurately.

 

[LionelHutz]

and spectacularly blasted through the pool deck slab like a kill-shot.

Not only blasted through the pool deck, they turned back under the building and knocked out the building columns.

 

[KingBobo]

And as I remember PH cantilever roof projected out further into space than 12 floor cantilever and parapet.

Above still is grabbed from this 4K pre-collapse drone footage:

[URL unfurl="true"]https://www.youtube.com/watch?v=VM416Xg-oBQ[/url]

 

[MechinNC]

I too am puzzled by the timeline with the folks coming up out the garage to the lobby. Come up the steps, get in elevator, ride elevator up, alarm sends elevator back down, arrive back in lobby to heavy dust. Maybe that dust was from the patio collapse. But reading other accounts, it sounded like they exited the elevator and exited the building right as the building collapse began.

So where does the few minutes between patio collapse and building collapse fit in with what this crew saw? Presumably the garage collapse as seen in the tic tok vid had not happened yet while they were in the garage.

 

[CE3527]

SF Charlie - I'm still thinking no on the slab on grade removal, but my only real basis is I think the water would be muddier and the small skidsteer wouldn't be gliding across the exposed subgrade that easily. The portion of what appears to be an elevated slab (just above the skidsteer) in the beginning of the video is interesting to me though, not sure why they seem to be preserving it, at least for the time being. Best guest: personnel access from top side to pit, I see the rope there.