Miami Beach, Champlain Towers South apartment building collapse, Part 07 90

[Seppe]

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Previous thread (Part 06)
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https://www.eng-tips.com/viewthread.cfm?qid=485223

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[Spartan5]

There has been a lot of telephone game and paraphrasing of witness statements both in the media and on this thread - but because they were on the spot what they saw and experienced is extremely important and needs to be accurately documented.

For example:

First, Cassondra was on her balcony (which afforded a clear view of the pool deck) at 1:30am, upset, and calling her husband in D.C, waking him up.

It seems pretty conclusive that the building had collapsed by then.

Not saying it wasn’t reported the way you’ve portrayed it. But supporting links back to those sources would have been helpful.

 

[MikeJ65]

I was going over some of the NIST photos and found a few things of interest:

It looks to me like this was a pool slab with original tile on the right and a planter on the left. Look at the concrete deterioration under where the planter would have been.

This one shows another piece of slab. I am assuming that the rebar loops are beam stirrups and that this slab may have been at a slab step. What bothers me is how clean the 'fracture' is. This looks more like a crack that propagated over time than something that happened suddenly. If they are beam stirrups, the beam must have just turned to rubble.

Possible punch shear and more bad concrete under a planter?

I don't like the dark gray surface where the floor connection would have been. Again, this looks like something that was like this for awhile, not a sudden fracture.

Any thoughts?

 

[Tropmet]

Microwizard thanks for pointing out that time, that was from a Miami Herald article and I will remove that reference to the time.

Regarding accuracy, that is why I have grouped corroborating quotes together.

I do think there is quite a lot to be learned from witness statements to the press (probably the interviews with NIST would be much more detailed and eventually we will get to read them) and they should not be dismissed wholesale as unreliable, especially as my focus was not on a quantitative timeline so much as comparing what was experienced and seen. For instance, I would not expect Mr. Stratton to forget his last words with his wife, and I found it telling that scattered among different news articles both Nir siblings had similar observations and timelines.

It was news to me that Gabe Nir saw dust coming into 111 from the patio doors, as that was only noted in an AP article and not in the WAPO article. I have tremendous respect for the AP. This is an important bit of information and was not noted on this forum prior or in any other news article.

 

[3DSoftwareDev]

I don't think any slab with remnants of tile and grout lines like that would be from the pool deck. The pool deck slab had a waterproofing layer, a layer of sand, then pavers (and maybe other layers), but not tile that was attached directly to the slab.

In fact, the second-to-last photo looks like a balcony slab to me. The corner seems to be curved just like the balconies, and again, the evidence of tile on the slab would be more consistent with a balcony (or perhaps an interior floor). But the curve to me is a big indicator that this was a balcony slab.

 

[dik]

@Tropmet... excellent summary.

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

-Dik

 

[AtomixPro]

This is incorrect. They did not see the garage ceiling collapse. Instead, they heard a loud noise while swimming in the pool, got out and went over, and then saw rubble and a gushing pipe in the garage entrance. Adriana Sarmiento started videoing at 1:18 am.

At best it's ambiguous. The husband of the tiktoker was interviewed and said "The first thing that we saw was something fall down". His gesturing was as though some slab or ceiling came down. The reporter preluded by explaining that Castilero "saw the ceiling of the first floor of the Champlain tower cave in".

This interview was on June 24 before the tiktok video went public and the theory of the patio slab preceding the collapse went mainstream.

Starts at 1:16

https://www.youtube.com/watch?v=BvkRmtmB-Fw&t=78s

 

[Nukeman948]

Possible punch shear and more bad concrete under a planter? Any thoughts?

Link
This is the same chunk featured in the first photo from this post. It's number 9 with a number 12 near it. If it's from a balcony I would guess the hole was cut in it to facilitate lifting.

 

[tmwaits1]

[/quote

At this point it’s pretty clear that the collapse of the building was preceded by the collapse of the pool deck. As to whether the pool deck failed spontaneously or it’s failure was caused by something falling from the roof is very much an open question. I don’t know why people seem to be certain of one or the other of these scenarios as they are both plausible and supported by plenty of circumstantial evidence. I look at the first second of the surveillance video which seems to show a missing section of the parapet along the roofline prior to the main collapse. We know from the plans that the parapet connection to the roof deck was very weak and it wouldn’t take much to knock it off the roof. As to the spontaneous punching shear failure, I’m less certain. I’ve inspected, analyzed, and designed reinforced concrete structures in coastal areas for more than 20 years and what I’ve seen is that usually a failure like what happened with the pool deck would be preceded many days of heavy, noticeable, cracking and abnormal deflections. Another thing that my experience has shown is that usually in these cases the original flawed design is a major contributing factor. I looked at the plans early on and found at least half a dozen mistakes.

 

[MaudSTL]

We’ve been following the same research path to try to understand what the witnesses heard and saw. My goal has been to create a timeline that sequences what witnesses experienced.

Many media outlets are paraphrasing the source interviews and we should interpret all of these secondary pieces, not just the NY Post, with a grain of salt.
[ul]
[li]Human beings who have survived a trauma generally recall important elements or snapshots until they have had time to piece together a narrative in their own minds. So the earliest survivor interviews are more like snapshots, and the later interviews are more narrative, and include additional details, like the dust, from secondary recall.[/li]
[li]Everybody is the star of their own show, with each personal narrative overlaid on their personal snapshots. So we also need to consider whose POV we extract meaningful information from, and also whether they’ve had time to commiserate with the members of their cohort to develop a cohesive group memory. The Nirs are a cohort of three, Nico Vazquez is a cohort of two, and Ileana Monteagudo is stand-alone.[/li]
[li]

In the case of the Nirs, we also need to consider that they have been the most interviewed, and media narratives have developed around Hero Mom and Hero Son, which can obscure the hard, building-related details that would help this group’s inquiries.​

[/li]
[li]

In the case of Cassondra Stratton, we currently have no time stamp and only a third hand (Ms. Stratton >> Michael Stratton >> sister) account of what she said. I think we need to wait for more direct information from Michael Stratton to get the greatest value from Ms. Stratton’s final moments in 410.​

[/li]
[li]Every single survivor is speaking English as a second language. So we have to be careful about judging the accuracy of word choices. Sometimes people can’t find the right word, especially in a second language. It stands to reason that they will find better words to describe their experience after they’ve had time to process the trauma. This places great value on good translations of direct interviews in the survivors’ first languages, Hebrew and Spanish.[/li]
[/ul]

Among the primary source interviews with the Nirs in 111 are Jeff Franco (Gabe,) CNN (Sarah and Chani,) WaPo Sarah and Gabe,) and Channel 13 in Israel (Gabe,) which is reported on by the Times of Israel. I think the Israeli Channel 13 interview is important, because Gabe had had time to process his experience and he would have been speaking in his first language, Hebrew. I am planning to see if my Israeli friend can find the Channel 13 interview and help us get an accurate translation. One thing to keep in mind about Sara Nir’s statements is that, unlike Gabe or Chani, she was looking at her computer/phone during the first collapse, so she has the most accurate time sense at that point. She has been consistent over multiple interviews that the first collapse (crashing wall from above) happened at 1:10. The WaPo reports that she put down her phone to go to the lobby at 1:14, which a lot of secondary sources have mistakenly picked up as the time she heard the first collapse.

The primary source interview we have so far with Nico Vazquez in the garage and lobby is his Spanish WhatsApp statement, which he made on return to Argentina. So by that time he and Gimena Accardi had had time to process individually and as a cohort with a shared experience.

The primary sources for Ileana Monteagudo in 611 are her WaPo interview in English and her Telemundo interview in Spanish. I wish we had a good translation of the Telemundo interview because we might be able to figure out exactly which wall the crack was in. Ms. Monteagudo gestures to her right when she describes it, but we don’t know which way she was standing at the time she saw the crack chasing down the wall…back to balcony or facing balcony?

 

[gonefishing2]

Edit the more I look at the image below, the more it looks like the rough raised area is part of the slab step down, and this is where the first patio was outside 111. It may have had tile in that area next to wall, as that was unit 111’s private patio area.

Or more likely from 211 floor and cantilever above? I think it has been posted there were beams between floor 1 and 2?

Edit 2: The crack Sara Nir saw could have been the outside wall peeling away from inside walls as column buckled between Unit 111 and 211.

I keep saying to myself, I will not do another post, but then Tropment makes an excellent post, and then the photo below is posted.

Here is what I see in the photo with my 'Vintage Peepers'

I believe this is a cantilever slab coupled with some of the slab from inside a condo unit. The red arrow points to a rebar like you would have if this happen to be a cantilever with a poorly tied parapet wall sitting on it. Or perhaps this slab had a masonry wall sitting ontop of it where the rebar is?

The green arrow points to where the slab cracked between possibly a condo wall/column line and the outside cantilever deck. It looks like thickset maybe was floated on the inside portion of the slab fragment.

I too think the grout lines indicate cantilever that had tiles mortared/adhesive bonded directly to top of slab with no water proofing layer in between.

I also think thickness based upon the other pictures is around the 6-8" mark vs the 9.5" patio slab.

I also see the bottom rebar appear to end at this fracture point, and not be continuous thru this possible joint or to termination say into an unreinforced CMU wall?

Edit: If you zoom in close, it appears there is one top rebar showing above the bottom rebar, so perhaps a column line at the crack and the rebar is a column tie on top of slab?

Edit 2: The holes at the curved portion in the other picture look like where handrails were inserted into slab...

 

[AtomixPro]

Here is my translation of Ileana Monteagudo's first interview. She indicates clearly where she saw the crack (the wall near the balcony door) coming from the roof, downwards. Her first interview was not with telemundo but AmericanTeve41, a local station while still at the Surfside victim center. I tried to keep the grammatical structure and order as similar as possible, not necessarily how an English speaker would say it, unless it would change the message being conveyed. I kept most of the filler words, and's, and run-on sentences as spoken. I indicated where Spanish idioms were translated into their equivalent.

https://www.youtube.com/watch?v=Dggm2FTyn9k

I was asleep and a supernatural force awoke me, that there was a bad ambiance [ambiente enardecido] in the apartment.

and I heard some strange sounds and I thought I had left the door of the balcony open. And when I went to the living room, indeed, the living room door was open, the one facing the ocean, the balcony.

I tried to close it and I could not. It appeared that the rail of the door had disleveled. ["y no pude. Parece que se habia de disnivelado el riel"]

And I hear another crack and when I heard that crack, I looked at the wall, I see a crack ["grieta"] coming down from the roof to the floor, of two inches in width.

Something told me this is going to fall.

I ran to the room, I removed my sleeping clothes, I put on a dress with some sandles. I went to the dining room and grabbed a purse with my ID and credit cards, pills, keys and my neckalace which I had taken off. I turned off the Virgin's candle. And just in case (Spanish saying "por si las moscas") I closed [or locked. Ambiguous] the door.

I did not know where the emergency stairs were. I went to the elevator which was much farther. I did not know that I had two emergency stairs next to my apartment. If I had known that there were two stairs next to my apartment I would have gone through there thinking that they would be faster.

Well, in the far stairs, as I arrived at the 4th floor, coming from the 6 to the 4th, I hear such an infernal noise, that I knew that part of the building had collapsed.

I saw the security guard, skinny like this (raising her finger), a kid, who said "there was an earthquake! there was an earthquake!", and I told him no this isn't, THIS building collapsed.

I scraped my legs, but I arrived to the level that I needed to be at. Later there was an enormous gap that I needed to jump over. One obstacle more to get to the street.

And I couldn't but god placed an obstruction that served me as a step. I put my foot on that step with my left leg and with my right leg I was able to reach over to firm ground.

 

[microwizard]

I found it telling that scattered among different news articles both Nir siblings had similar observations and timelines.

If they are accurate, then why aren't they identical? If they are different, whose version is correct? Even if one witness is 100% correct in all their observations, there is no way to tell which one. Hearing is an even worse sense than sight, it can be very hard to tell exactly which direction noises are coming from.

Did any witness say they *saw* something, anything, falling from the roof? If not, there is no reason to think anything did.

But we are asked to believe something on the roof suddenly decided to lurch sideways, knock out the parapet, which then coincidentally lands on the weak patio, initiating collapse at the garage level. This is magic bullet stuff!

Or the garage level collapsed.

Which is more likely?

NIST are analysing concrete and rebar. They are not asking witnesses "so, where do you think the collapse started?"

 

[emtv]

The primary source interview we have so far with Nico Vazquez in the garage and lobby is his Spanish WhatsApp statement, which he made on return to Argentina. So by that time he and Gimena Accardi had had time to process individually and as a cohort with a shared experience.

The earliest publications that I could find which refer to that voice message are dated June 24th so I'm not sure they had time to return to Argentina and process much yet. Other than that, your timeline is really useful for trying to piece together the sequence of events as these people experienced them. Thanks for putting it together (you, and Tropmet for scanning and comparing the various statements).

 

[gonefishing2]

I would hope Miami-Dade Police and the Judicial Branch are investigating the Crime Scene to include Witness Testimony and not NIST directly.

I would also expect NIST is focused on gathering the physical data from the collapse to populate their models with.

Bottom Line, they both have a role and should be focused on their respective piece of the puzzle.

I see both groups gathering the facts and evidence without being closed minded as to what was the trigger.

They both have their lanes, one is from a legal perspective and the other is from an Engineering perspective..

 

[dik]

and they should investigate the reasons for toppling the rest of the building to see if there are any other reasons than safety...

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

-Dik

 

[AusG]

In reading the back-and-forth here for days it seems to me that the early roof vs non-roof debate has created a binary distinction that is coloring later discussion. The various witness statements of noises "above" does not mean "on the roof" necessarily, and even problems originating on or near the roof does not necessarily imply a claim that the roof collapsed first. Strain in the fabric of the building could be bringing down ceilings in apartments all over, and the distribution of noise and vibration through the columns has been mentioned several times. "Above" is a relative term.

While also I think it's possible that resident stories of heavy machinery, vibrations etc on the roof are shaded by perception and their dislike of disturbance to their homes, but would we really be shocked if it turned out the roof work was one more non-trivial insult to a terminally weakened structure? It does not need the roof to have collapsed first for this to be true.

 

[Spartan5]

and they should investigate the reasons for toppling the rest of the building to see if there are any other reasons than safety...

Like what? To protect the structural engineering firm that had been contracted for more than $500,000 to analyze the structure and design repairs?

 

[gonefishing2]

Ausg, Yes, IMO the hammer drilling and activity on the roof was just the near final vibration induced event that may have started slab or beams to collapse due to shaking of tired under nourished and neglected structural joints.

Perhaps the rain was the final blow to an already weakened structure due to corrosion, chemical changes in soaked concrete and loose joints from N-S racking movements from vibrations next door and 3.9 after shock.

She was definitely appeared to be ready to go any minute

 

[Auri]

.. and Channel 13 in Israel (Gabe,) which is reported on by the Times of Israel. I think the Israeli Channel 13 interview is important, because Gabe had had time to process his experience and he would have been speaking in his first language, Hebrew.

You make excellent points about snapshot/narrative and cohorts, though to me it's clear Gabe and Chani are English native. Only their mother isn't. Times of Israel is a news aggregator; sometimes editors at such sites will add their own spin... but their primary source could as well have been Channel 13 Tampa (Fox) or Orlando (Spectrum/radio).

Probably the most "snapshot" source is the 911 recordings (

https://www.youtube.com/watch?v=gXGIWSkfW1s).

At 01:16:27 the first call comes in, a woman with a confusing accent reporting a big explosion, which she corrects to an earthquake - that seems to be the security guard relaying Sara Nir, who never grabs her phone but would have felt the ground slab shake from the plaza collapse. At 01:16:39 the alarm company notifies the police - so it would seem the silent alarm tripped on the garage after all. At 01:21:57 Gabe Nir calls, and by this time he's on Collins Ave. as we hear a Miami-Dade employee confused about the address. The loud rumble of the full building collapse is audible at 01:22:20 +/- 1s if the 911 tones are accurate in time. That's over 5.5 minutes between plaza and building collapses, meaning there was plenty of witness time lost to confusion/standing around as opposed to full-on panic.

As for the Argentinian actors, I've found almost zero primary source detail; pretty much the only good account I had to get from translating a news article:

https://www.infobae.com/teleshow/20...mi-cuando-se-derrumbo-se-salvaron-de-milagro/

It seems one or both of them heard a strange "creak" before entering the elevator, then the actual plaza collapse happened while they were inside. The rest basically says they didn't escape as aggressively as the Nirs, perhaps stopping to help others.

 

[Demented]

@Thermopile
@MikeJ65

If I am not mistaken, that balcony slab belongs to unit 511.

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