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Miami Beach, Champlain Towers South apartment building collapse, Part 03 148

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Js5180 (Computer)4 Jul 21 18:19 said:
I’m thinking the round object is a ventilation fan
Good sleuthing, I was wondering was a washing machine could be doing there, but your fan, as pictured, is much more plausible.

SF Charlie
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For anyone not familiar with them, the Loizeaux family / CDI are pretty much the best in the business at precise demolition with explosives. If anyone can drop it neatly into its own footprint and the available western plaza deck, it's them. Loads of their past projects here:


The heavy F-350 thing was just my invented unusual hole as part of a hypothetical example of how the Swiss cheese model can make a 40 year old latent defect suddenly be significant in a failure. In my example, it was a way of quietly doing damage to the surface parking area, that reduced the remaining structural margin and explained the failure over there. I have no evidence to say something like that happened, but the ongoing construction work makes the scenario of a heavy vehicle up there a possibility.
 
I don't think the officials will give much info on when the demolition is going to take place. They don't want a crowd, and it's certainly not appropriate to make an event out of it. When they're ready, the police will block the streets, make sure the area is clear, and it'll all be over in an hour or less.
 
"If you want to go get your pet, read and sign this release form. The two people next to you will also sign it, affirming you read it. Don't dawdle, as there's others waiting to go up. And don't slam any doors. Good luck."


spsalso
 
Lukeuk99,

I was new a few days ago, and the folks here are pretty nice, though if you're wrong, they're likely to tell you so.

A thing that I saw in that video was concerning to me. It has the patio slab tied mid-height to the columns under the building. Why'n holy hell did they not just put up another adjacent post? Then when the slab fell, it wouldn't have pulled the building column down. One reason is that they didn't think of it. I didn't until I saw the video.


spsalso
 
Welcome both of you and any other new guys... we'll generally correct you in a friendly fashion...

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

-Dik
 
Lukeuk99,
Welcome to the site. That video illustrates very well one of the main theories as to how the collapse occurred, discussed here but not with graphics like that. And spasalso's idea of a joint between the pool deck and the building proper has also been discussed here and supported. That gets into the area of concept design, in which the structural, architectural, and financial considerations often clash.
 
First off, this demolition is extraordinary on so many levels, but Kilsheimer's analysis is equally as dire in that the structure only has a windloaded capacity of 45mph sustained, 60 mph gust @ a safety factor of 1.

It appears that this is not going to be an implosion where the structure drops or "pancakes" in place, but is designed for lack of a better word "hinged" to fall (slide) forward (To the west on top of Collins St) basically intact

From an structural standpoint, it will be interesting to see how the sheer walls that constitute the cores(stairwells, elevator shafts) fall, or don't fall.
 
Press briefing just now from the mayor confirms 10pm-3am ET window for demolition.
 
Keith_1 said:
it will be interesting to see how the sheer walls that constitute the cores(stairwells, elevator shafts) fall, or don't fall.

With such little shear walls in the E-W direction:

SHEARWALLS_ahuzk5.png
 
Shoring the building is not an option. No HUSAR team would risk lives to shore an empty building for the sake of evidence of unknown value. And who would survey the building and what engineer would approve the plan when no-one is sure yet what the cause of collapse was? And what engineer would allow crews to work in a building that has been declared unsafe? It would be weeks and dollars and risk of more lives lost.
 
Apparently as of May 26, 2021, there was a crane on 88th (north side of building) with outriggers sitting on the garage structure carrying roofing supplies and "tar" to the roof. Maria Notkin of Apt. 302 made the initial complaint - she appears to be the same unit who called their relatives from their landline multiple times after collapse. They were asking for the crane to be moved from 88th to Collins, the association said they needed the crane on 88th to reach the entire roof. See page 40 of email communication documents uploaded by the city. Link

Also, the way the parapet ripped away from the remaining shear wall over the x10 units is intriguing - while most of the building ripped from the shear wall cleanly due to high force, the roof parapet did not. There was a column roof anchor into this wall. If the parapet and balcony fell onto the pool deck it would have fallen into the column that was damaged per the ENR article at about 60 mph per another post above. Per an on-site engineer, again in the ENR article, the backside of this column had impact damage clearly not from a vehicle, the transfer beam also had damage. This column damage appears to have been what caused the pool deck to collapse due to the damage pattern.

A roof anchor location hypothetically causing the roof and 12th-floor balcony to collapse is in red below. The damaged column causing pool deck collapse (per ENR report) is in blue below.
roofanchor9_ybkzgz.jpg
 
Ingenuity said:
With such little shear walls in the E-W direction:
Hopefully, they are able to collapse it all the way due to the transfer beams.
The same company made this mistake in 1996 due to a similar transfer beam issue.
haciendaJPG_pclgme.jpg
 
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