Miami Beach, Champlain Towers South apartment building collapse, Part 14 41

[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
Miami Beach, Champlain Towers South apartment building collapse, Part 06
Miami Beach, Champlain Towers South apartment building collapse, Part 07
Miami Beach, Champlain Towers South apartment building collapse, Part 08
Miami Beach, Champlain Towers South apartment building collapse, Part 09
Miami Beach, Champlain Towers South apartment building collapse, Part 10
Miami Beach, Champlain Towers South apartment building collapse, Part 11
Miami Beach, Champlain Towers South apartment building collapse, Part 12
Miami Beach, Champlain Towers South apartment building collapse, Part 13

SF Charlie
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[Jeff Ostroff]

Good morning Vietnam! Glad to have Part 14! up and running. Can't promise I won't stop talking about palm trees, though LOL!

 

[SwinnyGG]

As long as we move on from pavers..

 

[SFCharlie]

Maybe we could talk about Demented(Industrial)'s post at 10 Oct 21 18:37 on part 13 and answer the question "Still just as confused. So I guess, wtf is that rebar cage?"
or
Maybe we can talk about if we can tell what fell first the valet parking or the planter from the witness statements? The tourist video was after the valet parked cars sank, but who knows how long the garage was full of debris before the tourists noticed?
Just asking.

SF Charlie
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[AusG]

Just a thought on that beam sitting on the floor, position thereof. A beam connection is the last thing you'd expect to punch through, right? So in the general collapse maybe the columns under the beam buckled or leaned over, not punched, so the beams will be laterally displaced from where they started out by maybe the length of a column or so.

 

[Demented]

Or it was pushed around in the clean up. It looks to be in the correct spot, but that cage is where the drive path was. What's odd is there doesn't appear to be another cage or column base on the west hand side opening of the beam section.. It didn't move North, as we still have 4 column rows north, and 2 east. Pointless though. I'm pretty sure I'm just lost in shitty photo perspectives.


EDIT: Oh yeah. Piles; has anything been said about those? Last I recall we still didn't know if precast driven or Franki/PIF was used.


@SFCharlie.
So there was that January 2019 complaint about fears of work too close to the property line and damage to the property, but political BS. Other than this spot, the perimeter wall appears to be in much better condition with no cave-ins. A little over 3 years is a decent time for a damaged support wall to have a vibrating and changing load on it.

 

[MaudSTL]

Maybe we can talk about if we can tell what fell first the valet parking or the planter from the witness statements?

We have already talked about this in past threads, so I see no value in rehashing it. But, to review, no, you cannot tell a deck collapse sequence from witness statements.

We know from Jinal’s structural analysis where the weakest part of the deck structure was.

We know that Elena Blasser in 1211 was awakened by unusual loud cracking sounds the previous morning, sometime between 3 and 4 AM.

We know from the banging sounds heard in 111 from 11 PM on that something was already changing in the deck or building. We don’t know if these sounds were heard elsewhere, or if they started earlier.

We know that something fell loudly at 1:10 AM, and was heard from 111 and the lobby. We don’t know what fell or where it fell.

We know that Nico Vazquez and his wife Gimena Accardi were in the garage elevator vestibule just before the deck fell at about 1:15 AM, and they heard odd loud cracking sounds a few seconds before they got on the elevator. They were actually in the elevator when the deck collapsed. The Vazquezes did not state that they saw any debris in the garage before they got on the elevator. That’s not to say that a piece of ceiling couldn’t have collapsed in an area that they didn’t look toward. However, we don’t know what space they parked in or what path they walked to the elevator.

We know that the only witnesses (Sarah Nir and Shamoka Furman) who saw the deck collapse at about 1:15 AM saw it from the lobby, so they were looking at the parking deck near the lobby. Neither of them reported having looked past the parking deck at that time.

We know that Adriana Sarmiento and Roberto Castillero were in the pool area at the Bluegreen Resort, and heard the deck collapse at about 1:15 AM. They made their way over to the street and videoed the debris within the garage viewed down the garage ramp at 1:18 AM.

We know that Cassie Stratton in 410 told her husband that the pool deck had collapsed when she spoke to him in the moments before the building collapsed at 1:22 AM.

>>>>>Edit: charlieSF favors PPTs and I favor spreadsheets. So here’s a spreadsheet version of all this text. I can add a column for Why if anyone has any explanations they’d like me to add.

 

[SFCharlie]

Thank you!
Jeff Ostroff
SwinnyGG
AusG
Demented
sgw1009
MaudSTL

so, "something fell loudly at 1:10 AM", "just before the deck fell at about 1:15 AM, and they heard odd loud cracking sounds a few seconds before they got on the elevator. They were actually in the elevator when the deck collapsed", "saw the deck collapse at about 1:15 AM saw it from the lobby", "heard the deck collapse at about 1:15 AM. They made their way over to the street and videoed the debris within the garage viewed down the garage ramp at 1:18 AM.", "the pool deck had collapsed when she spoke to him in the moments before the building collapsed at 1:22 AM" Thank you Maud!

SF Charlie
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[AusG]

And there had been those cracking noises the previous am too. The building was being strained somehow. The catenary of incipient sag in the deck is to me a credible, large force not obvious to the casual eye. But from when?

We see the odd situation near the pool where the upper nonstructural material did not punch when the slab did. Perhaps the structural part of the pool deck was pulling hard on the columns for days, with small deformations masked by the upper layers and not noticed underneath in a dim corner of the garage. I know this requires two ifs and two ifs are worse than one, but otherwise we have to be buckling columns or punching slabs inside the building.

 

[MaudSTL]

The catenary of incipient sag in the deck is to me a credible large force not obvious to the casual eye. But from when?

“From when” is a really good question. To speculate, I can imagine the deck sagging increasingly for a day or even longer, pulling at three facade columns in the x11 stack. Could there have been enough force to have started one column, which happened also to have been having an anchor installed in it, to buckle and wake up the late Ms. Blasser in 1211 22 hours earlier?

I keep wishing some investigator would talk to survivors and see if anyone heard the banging sounds, which increased in intensity over time, earlier than 11 PM. Could these banging sounds have been the deck continuing to sag until finally a delaminated ceiling section fell into the garage at 1:10 AM? This was just five or so minutes before the deck finally punched through and collapsed, enough time for the Vazquezes to park, walk to the elevator vestibule, hear loud cracking sounds, and get into the elevator.

All speculative, of course. Maybe this is not a good way to use this forum. But there’s just not enough publicly known data to to do more than speculate, is there?

 

[Jeff Ostroff]

The piles were Frankie/PIF Piles

 

[Demented]

Link to findings? Or just going off original drawings?

Precision guess work based on information provided by those of questionable knowledge

 

[AusG]

The audits will identify buildings with poor documentation, and maybe shortlist some with poor designs/ concrete etc. But there is a fundamental problem: the buildings are all like CTS before June 24: "Hey, it's stood fine for 40 years". Condemning, and kicking out residents with some buyback scheme is going to be expensive and litigious, and where would you stop? None of them will be perfect but few of them will actually fall over.

I could make a case for retrofitting a couple of simple accelerometers into older buildings, set a baseline of background creaks and groans, and review anything else for more serious symptoms. Our SE's have never been happy with outright collapse with no warning. The likely case here is that warnings went unrecognised. Rather than wait for the perfect testable smoking gun that may never come, why not wire up the worst of the shortlist for actual signs of a problem? Probably cheaper even than having the whole place pulled apart for concrete coring and the like (whoops sorry mate, cut that rebar, never mind)

People put up with false fire alarms with weary acceptance. Building-killing vibrations could be set apart from background a little more clearly so there will be less crying wolf. Just a thought, but I like measuring things.

 

[Reverse_Bias]

Just a reminder, I've seen columns bigger than 16x16 holding up the roof of a Walmart.

Also some 24X24 columns that were damaged by the deck cave in and did not collapse, only the 16x16 ones did.

 

[Jeff Ostroff]

Some of the columns under the parking deck were also 16 x12, don't forget. And if you have forces tugging in the wrong direction, you really only have a 12" column.

 

[MaudSTL]

S. African Architect Mike Bell has posted a new video with animations.

https://youtu.be/WdkdIUdJLEk

 

[MaudSTL]

USA Today investigates construction project corruption in 1980s Miami.

https://archive.is/dEJbC

>>>>>Edit: The same story picked up by Yahoo News retains the embedded content better than the archived version.

https://autos.yahoo.com/autos/left-rot-collapsed-condo-born-090209489.html

 

[zebraso]

S. African Architect Mike Bell has posted a new video

His "lever arm force" as the culprit is what I believe has been discussed here for quite some time as "catenary" action of the relevant beam slab arrangement of the pool deck connection to the building proper. I think this has been mulled over quite a bit and has not been rejected.

 

[Reverse_Bias]

USA Today investigates construction project corruption in 1980s Miami.

https://archive.is/dEJbC

>>>>>Edit: The same story picked up by Yahoo News retains the embedded content better than the archived version.

https://autos.yahoo.com/autos/left-rot-collapsed-c...

It does a really good job explaining where all that white dust came from.

Seriously though they did do a good job tracking down 80s drug kingpins in prison and getting the inside story of that building.

 

[Debirlfan]

I don't think it's been mentioned here, but I've read that in at least two cases, walls were removed between units to turn two units into one large unit. Also possible that some interior walls were removed within units to create a more open floor plan. Even if they weren't (supposed to be) load bearing walls, it doesn't seem like this would have helped the structure.