Miami Beach, Champlain Towers South apartment building collapse, Part 11 54

[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


SF Charlie
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[zebraso]

SECOND FLOOR FRRAMING PLAN

Is this covered by the 2nd through 9th being the same layout? I actually don't know. Just asking.

 

[Vance Wiley]

I do not know if the framing is the same as regards columns and slab reinforcing. They did intend to reduce the concrete strength above some level - perhaps the 8th floor?
The vertical load design would be the same for floors 2 and above, with the roof slab likely different (less load?).
The lateral design would increase the moments in the slabs and columns as the distance from the top increases.

 

[Jedidad]

how did a column "impale" the hallway on west side of the shear wall? 

Maybe they just saw a column that had been exposed by falling drywall/framing during all the swaying.

 

[gonefishing2]

@Optical98 and Jedidad

Was it a column or concrete roof beam supporting the large common areas AC unit? I have no idea, but the RC roof beam was large that was supporting the large AC unit and it was almost due North of Elevator shaft.

A lot of posters had said the columns were fine in axial loading, but I do not remember seeing any analysis of the lateral stability of the slender columns in the collapsed section, and the effects of drift on the flat slab to column joints. Especially the effect over time if those joints are being stressed due to say uneven loading of 2-ways slabs, wind loading, construction vibration next door, etc. Seems to me those under nourished flat slab and slender columns were being over stressed in at least E-W direction, and time would be the enemy if drift is excessive.

Also no one has discussed the effect of the too much rebar in the slender columns of the collapsed portion, as mentioned in Miami Herald Investigation.

 

[MaudSTL]

You're now famous >>

https://www.youtube.com/watch?v=9Hd2U8ELJpY

Thanks! I had no idea! This will take several seconds of my Fifteen Minutes of Fame.

On another topic, I have the impression that there may be some confusion around the timeline. In case I am right, following is some clarification.

"Sara Nir was up late, checking her email when she heard knocking sounds that went from a soft tapping to hard pounding to a frightful crash overhead -- as if a wall had collapsed in the unit above her ground-floor condo.” 
…
Nir is describing something tipping (knock knock knock) and falling over.
…
Furman thought something hit the elevators as well.

This is the same knocking that Chani Nir heard when she got home at 11 PM. We still do not know if the security guard also heard it, or if anyone heard it prior to 11 PM.

The knocking is followed by the the first collapse at 1:10. This is what made Sarah Nir go to the lobby to complain.

It's amazing Monteagudo (611) escaped. You'd have to think she must have already gotten to the stairwell while Nir was in the Lobby.

Ileana Monteagudo was awakened by the second collapse: the deck collapse. While she was waking up and going to check her sliding door, Sarah Nir and Shamoka Furman, who were in the lobby discussing the first collapse, heard the second collapse. Sarah ran over to the window and saw the surface parking part of the collapse, and then ran to roust her kids. At that point, Ms. Monteagudo was seeing the crack run down the wall of her living room…we still don’t know which exact wall was the one where the crack was opening.

…the only thing I could think of is if we consider the 904 survivor details that seem to indicate that some of the top floors dropped 1st, to the 8th and maybe just to the west end ( x4 and x10), that could have blocked 811's exit.

Raysa Rodriguez was sleeping in her room on the ninth floor when she awoke disoriented. The building was swaying "like a sheet of paper." She ran into the hallway to find that it had been impaled from floor to ceiling by a concrete pillar; the doors of the elevators were shorn off, exposing the shafts."

And how did a column "impale" the hallway on west side of the shear wall? 

Raysa Rodriguez woke up as a result of the third collapse: the collapse of the building. How does her statement describe a pause in the early part of the collapse that occurred while she was still asleep?

 

[Demented]

I do not know if the framing is the same as regards columns and slab reinforcing. They did intend to reduce the concrete strength above some level - perhaps the 8th floor?

-1kPSI concrete for 9, 10, 11, 12, 13 from lower levels.

 

[Optical98]

All About Money and Jedidad

"Was it a column or concrete roof beam supporting the large common areas AC unit?"
"Maybe they just saw a column that had been exposed"

Listening to Furman on these videos, she heard something hit the elevators/shaft, she points up.... Raysa is pretty descriptive and she is on the 9th floor.

And I can't find the source right now, but I remember reading someone saying that the elevator shaft was lurching into the hallway, I was thinking this is odd because we can't see anything outside the shear wall.

So I think something fell and hit the shaft.

Below again is the exact quotes from the article, in case AAM didn't see my post.

"Sara Nir was up late, checking her email when she heard knocking sounds that went from a soft tapping to hard pounding to a frightful crash overhead -- as if a wall had collapsed in the unit above her ground-floor condo. 

Raysa Rodriguez was sleeping in her room on the ninth floor when she awoke disoriented. The building was swaying "like a sheet of paper." She ran into the hallway to find that it had been impaled from floor to ceiling by a concrete pillar; the doors of the elevators were shorn off, exposing the shafts."

^From this article -

https://www.cnn.com/2021/07/03/us/surfside-condo-c...

Nir is describing something tipping (knock knock knock) and falling over.
And how did a column "impale" the hallway on west side of the shear wall? 

"Metallic boom" was heard and Furman thought something hit the elevators as well.

 

[Optical98]

Maud,

My post is more about what was happening on the 8th and 9th floors... why the couple in 811 had the time to gather their IDs and then embraced each other, they were found this way, as if they couldn't get out. 904 mother and daughter end up on 8th flr long enough for the mom to crawl over and cover her daughter...before they descend further.

I'm not proclaiming time-stamps, though Furman makes it pretty clear she first heard booms from above thinks it's the elevators, then the 2nd boom was the pool deck.

None of this has anything to do with "Chandi in the shower at 11pm"

 

[gonefishing2]

Optical98,

If I am not mistaken, the elevator doors would be set in CMU infill walls. If the doors are gone, odds are the CMU walls around doors are gone too. All of that metal and CMU are going to fall down the elevator shaft probably, and make a hell of racket on the way down and when it lands on elevator car at bottom.... Building swaying would be worse the higher the floor, I would imagine.

 

[Optical98]

All About Money,,

That makes sense, could be what Furman heard first. Regarding Rayza seeing a column impaling the 9th flr hallway... I guess I'm gonna have to look at the plans again...

 

[Santos81]

If I am not mistaken, the elevator doors would be set in CMU infill walls. If the doors are gone, odds are the CMU walls around doors are gone too. All of that metal and CMU are going to fall down the elevator shaft probably, and make a hell of racket on the way down and when it lands on elevator car at bottom.... Building swaying would be worse the higher the floor, I would imagine.

The UPH corridor was part of a substantial beam group that was integral with both the Common Interior Condenser Support structure and the elevator shaft above the top of the shear wall. When this was ripped away just below the machine room, it caused the elevator assemblies to move. I’ve heard that the deformation was enough to allow the counterweights for elevator 1 (northern of the two) to come off the guiderails.

 

[MaudSTL]

…Furman makes it pretty clear she first heard booms from above thinks it's the elevators, then the 2nd boom was the pool deck.

I know that Sarah Nir stated that she perceived the first collapse as a wall collapsing in the apartment above.

And I also know that Shamoka Furman thought the first collapse had to do with the elevator, even though there were no alarms.

But what is new to me in what you are saying is Shamoka Furman perceiving the first collapse as coming from above. I hadn’t seen anything that indicated directionality. Would you please provide a link that I can add to the timeline?

P.S. Chani was in the shower at 1:10.

>>>Edit: Keep in mind that the elevator was still functioning as the deck collapsed. The Vazquezes experienced the deck collapse at 1:15 AM from inside the elevator, which brought them to the lobby “as usual.” So the elevator was working after the first collapse at 1:10 and through the second collapse at 1:15. Whatever happened to the elevator occurred after 1:15.

 

[Santos81]

Both drawings are titled SECOND FLOOR FRRAMING PLAN.
So they changed the Second Floor in order to add a penthouse? Probably due to added wind exposure so more drift moments in the slab and columns at the second floor level. The shears and moments for the slabs and columns are increased by one floor due to the addition at the top. Originally the First Floor slab and columns had similar moments because they were an equal distance ( same number of floors) from the top. And the First Floor slab was thicker, as I recall.
The columns have more vertical load and more bending if the penthouse is added. Were they increased in capacity as a result of the PH add?

You’re right on the money…no pun intended.

UPH required revisions to Foundation, Basement, Lobby, Second, and roof levels specifically for wind load resistance. The second floor framing plan with partial details and subtle but significant differences sticks out like a sore thumb. Legitimizes the rumors regarding a bought it yet to be obtained variance while simultaneously dismisses the suggestion the UPH was a later addition that wasn’t part of the original calculations.

 

[MaudSTL]

The second floor framing plan with partial details and subtle but significant differences sticks out like a sore thumb.

Could any of those differences on Floor 2 or elsewhere have resulted in a failure that would account for Collapse 1 heard on the first floor at 1:10?

 

[Optical98]

Maud,

"you are saying is Shamoka Furman perceiving the first collapse as coming from above."

I did not say she perceived the 1st booms as the 1st collapse.

Taking into account what All About Money says about CMU blocks possibly falling down onto the elevator cars...

And Santos

" it caused the elevator assemblies to move. I’ve heard that the deformation was enough to allow the counterweights for elevator 1 (northern of the two) to come off the guiderails."

I don't think it matters, people tend to point up when talking about elevators anyway.

 

[gonefishing2]

I think Santos81 explains the big metallic noise in elevator shaft, plus perhaps doors and CMU's falling. The Corridor Beams Santos81 mentions would explain the West side hall ceiling puncture very well. The after collapse photos show the elevator shaft about the 12th floor roof line has shifted and broken one or more columns where it attached to 12 floor roof. So the corridor beams and columns with CMU in fill were moving and falling perhaps very early.

 

[Optical98]

Santos,

Any idea why there seemed to be a brief pause of the upper floors collapsing to the 8th floor?

 

[BKNJ]

Yes, I noted that as well.. the only thing I could think of is if we consider the 904 survivor details that seem to indicate that some of the top floors dropped 1st, to the 8th and maybe just to the west end ( x4 and x10),

When I read 904's account (which I don't have handy to reread), I didn't get the impression that there was a delay in the collapse. IIRC, they were almost to the front door... The way I visualize the situation is that since the x04 units are the units that were torn in half, they were originally in a portion of 904 that was collapsing... and either due to the way the floor fell or due to their momentum from running to the door, they fell one story into a portion of 804 that hadn't collapsed... yet. As the rest of building behind them continued to fall past them, mother covered daughter... then once most of the building had fallen below the 8th floor, the section of 804 they were on broke off and they fell five stories onto the top of the rubble.

I don't know if this is a viable scenario, but it was what I got from the account I read.

I wonder if the front door to 811 was compressed by the failure that woke up the camera one story below them?

After watching the 711 video, the idea that the front doors may have gotten wedged and prevented people from escaping is one of the two things about the collapse that keeps me up at night (the other being that the eastern stairs led nowhere safe). Just curious, does anyone know what kind of doors they were? I think steel doors are required in NYC, and my friend's door is robust. I can run through most non-steel doors... but to escape their unit, it would be easier to rip a hole through the drywall.

BKNJ

 

[Optical98]

Demented

Quote (Vance Wiley)
I do not know if the framing is the same as regards columns and slab reinforcing. They did intend to reduce the concrete strength above some level - perhaps the 8th floor?

"-1kPSI concrete for 9, 10, 11, 12, 13 from lower levels."

^ This could explain the brief pause at the 8th floor?

 

[Optical98]

BKNJ

They got out the front door.

If they had run straight (doors face south) ahead instead of turning left...