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

[Seppe]

Continue...


Previous thread (Part 06)
[link ]

https://www.eng-tips.com/viewthread.cfm?qid=485223

[/url]

 

[dik]

you should add the previous links...

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

-Dik

 

[Spartan5]

An update on NIST’s progress to date. Includes a description of how they are documenting and collecting things, many pictures of the debris they have collected (alas, no AC), and some decent quality video showing the collapsed area. Looks like they are relying heavily on LIDAR and RFID tags, and conducting preliminary analysis using Ultrasonic Pulse Velocity (UPV).

https://www.nist.gov/news-events/ne...investigation-champlain-towers-south-collapse

 

[MaudSTL]

Copied over from 06.

**************

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.

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.

The timeline and 911 call timestamps are helpful in understanding what we currently know about this. Nicolas Vazquez's statements are difficult to evaluate by someone who does not speak Spanish and are subject to future clarification. ​

This is my understanding. Everything was happening very fast at that moment. Adriana Sarmiento's TikTok video starts after the Vazquezes got out of the garage. So her video is showing us what the garage entrance looked like right after the deck collapsed. By that time, the Vazquezes were up in the lobby with the Nirs.
[ul]
[li]<1:15 am: Vazquez/Accardi drive back from dinner, park in the garage, walk to the elevator, hear a weird cracking sound, get on the elevator[/li]
[li]~1:15 am: Deck collapse, witnessed from the lobby by Sara Nir from 111 and Shamoka Furman, security guard[/li]
[li]1:16:27 am 911: "A big explosion" "earthquake." This call may be from Shamoka Furman[/li]
[li]<1:16:39: fire alarm directs elevator to lobby[/li]
[li]1:16:39 am 911: Central Alarm Control calls in fire alarm.[/li]
[li]>1:16:39: Vazquez/Accardi exit elevator into smokey/dusty lobby, hear car alarms, see "sunken cars", and run out of the building with the Nirs just before the building collapses. In one interview, Vazquez said their entire experience occurred in less than five minutes. Sara Nir said that the building collapse just as they crossed Collins.[/li]
[li]1:17:49 am 911: "earthquake" "the garage" "something underground... everything exploded down." *May also be Shamoka Furman[/li]
[li]1:18 am: Adriana Sarmiento begins to video the rubble seen in the garage entrance.[/li]
[li]1:22 am: Building collapses.[/li]
[/ul]

What I am still baffled by is what Sara Nir heard at 1:10 am. She said it sounds like a wall collapsing. All three Nirs said in multiple interviews there were three collapses preceded by the knocking sounds (which Chani Nir says were already happening at 11:00 pm):
[ul]
[li]1:10 am: Sara Nir hears what sounds like a wall collapsing[/li]
[li]1:15 am: Sara Nir and Shamoka Furman witness the deck collapse[/li]
[li]1:22 am: All witness the building collapse[/li]
[/ul]

 

[Spartan5]

Sara Nir, 111, heard the first crash at 1:14 am.

The first thing she noticed was the knocking.
Then came a crash so loud, Sara Nir wondered whether a wall had come down somewhere in Champlain Towers South. And the second crash minutes after, in the lobby, where she witnessed the collapse of the car park.
Startled and up later than usual after an event, she put down her phone at 1:14 a.m. and made the short walk to the security guard in the lobby. The guard mentioned hearing the strange noises, too, but was unsure what to make of them.

Nir was still standing at the desk when a metallic boom reverberated across the building’s 12 floors.

Through the lobby’s wall of windows, Nir saw cars jutting out of the ground, some standing nearly upright, and the pool deck caved in. An earthquake, she thought, dashing back toward Unit 111, toward her kids.

This all correlates well with a collapse originating by the pool, and progressing toward the building.

The crash sounded above her because it was transmitted by the structural elements of the building around her. To me, it’s much more likely that that slab collapsing would sound like something above her than would something happening 12 floors up.

If we entertain the idea that the penthouse collapsed at 1:10, why would it be that no one on floors 12->11->10… were freaked out by it and called 911 and/or boogied on out of there? Especially if it was supposedly heard so clearly on the first floor?

In her first interview, she makes no mention of a noise like a wall collapse; describing the sounds as “construction knocks” or “renovation noises.”

https://collive.com/mother-escaped-with-children-right-before-surfside-tower-fell/

 

[CE3527]

MaudSTL - nice job on the timeline, lines up with the fragments that have been reported. The overall 7 minute timeline for a concrete building to come down continues to be astonishing and I still don't understand the fire alarm. I suspect failures in the garage with the circuits to the devices coming apart sent a signal to the monitoring company, but there isn't any evidence the alarm ever sounded in the building. If it had, 6 minutes pre-collapse would have been plenty of time to wake people up and get them out.

There does seem to be a conflict between Nir reporting a loud noise at 1:10 and Vazquez/Acardi entering the garage at 1:15. They'd essentially be driving directly under the Nir apartment so it's difficult to see how any significant failures occurred 5 minutes before they entered the garage. It could be the Nir's were hearing the beginning of the punch through failures of the garage deck which may not have been as noticeable early on depending on where you were in the garage.

 

[gonefishing2]

Spartan5, I enjoyed the NIST link. Hey looks like compression testing of core samples is old school now days with UPV. They have come a long way in Surveying since my college days walking all over campus with Optical Transit and Stick Man....

Edit: and a tape measure, plumb bob, etc.........

 

[Paul Austin]

Don't forget poor Cassondra Stratton statement about the pool collapsing and the building shaking. She was at the unit 410.

"Mike Stratton awoke to the sound of his cellphone ringing. It was his wife, Cassie Stratton, on the other end, speaking frantically about their condo building shaking. She told him she saw a sinkhole where the pool out her window used to be. he heard a horrible scream and then the line went dead"

 

[MaudSTL]

Here's some new info, so far as I can tell.

In reviewing some stories in Engineering News-Record, I found two pieces of information that may not have been previously discussed.

[ol 1]
[li]Jose Santini, a businessperson with a company that sells hurricane shutters, commented on an ENR article entitled, "Engineers Try to Fathom Factors Leading to Deadly Champlain Towers Collapse." In his comments, Mr. Santini states that at least two of the apartments in the part of the building that collapsed had 3" topping and tile added to about 2500 sf apiece. He did not name the two unit numbers, but did say he has photos available, and expressed his concern that this may have helped create an overload situation in a building with known subsidence. If anyone is a subscriber to ENR, you may wish to invite Mr. Santini to join this discussion and upload his photos.[/li]
[li]Along with the roofer working on anchors and more, T-Mobile's contractor was also up on the roof doing antenna upgrade work on a permit issued 4/30/21. The upgrade work is not further described.[/li]
[/ol]

 

[SFCharlie]

I'm still thinking no on the slab on grade removal,

I did not mean that I thought that they should excavate below the slab, I just thought it looked like they were doing that. Later in the day it looks as if they have sawn a hole in the slab and drained out a lot of the water.
First, they say they want a clean deck to show that there are no bodies left to be found.
Second, they may want to look at the pilings, I don't know.
Third, all concrete needs to be remove eventually to do whatever they will do with the property.

SF Charlie
Eng-Tips.com Forum Policies

 

[MaudSTL]

Don't forget poor Cassondra Stratton statement about the pool collapsing and the building shaking. She was at the unit 410

I am working on an updated timeline that includes Ms. Stratton's call as well as Eric and Tamar Zion's activities. I didn't include them in the bullet list because we have no timestamps, and can't be exactly sure where they fit in.

I am guessing the Stratton call initiates somewhere around the 1:18-1:19 minute mark. From the statement by her sister, it sounds like the deck collapse had already taken place, and the mortally wounded building was shaking and struggling to find a new equilibrium.

We also know from what Adriana Stratton experienced at the garage entrance that many people woke up and ran to their balconies to see what was going on. The poor people Adriana saw on their balconies at 1:18 were only there for four minutes.

 

[Paul Austin]

Thank you. I believe Ms. Stratton called her husband more or less at the same time Ileana Montegau from apt 611 started running towards the stairs and the Ringcam from 711 started recording.

 

[MaudSTL]

but there isn't any evidence the alarm ever sounded in the building

Apparently the fire alarm worked in the surviving part of the building, but only after the rest of the building had already collapsed. I have seen articles where Esther Gorfinkel, who lived in the surviving part of the building, said she heard the alarm. But they were never specific as to when she heard the alarm. This piece, describing what happened to Alfredo and Marian Lopez after both the deck and the building collapsed, says, "The lights cut out and the emergency alarm came on, warning the residents of Champlain Towers South to evacuate."

 

[Demented]

Here's some new info, so far as I can tell.

In reviewing some stories in Engineering News-Record, I found two pieces of information that may not have been previously discussed.

Jose Santini, a businessperson with a company that sells hurricane shutters, commented on an ENR article entitled, "Engineers Try to Fathom Factors Leading to Deadly Champlain Towers Collapse." In his comments, Mr. Santini states that at least two of the apartments in the part of the building that collapsed had 3" topping and tile added to about 2500 sf apiece. He did not name the two unit numbers, but did say he has photos available, and expressed his concern that this may have helped create an overload situation in a building with known subsidence. If anyone is a subscriber to ENR, you may wish to invite Mr. Santini to join this discussion and upload his photos.
Along with the roofer working on anchors and more, T-Mobile's contractor was also up on the roof doing antenna upgrade work on a permit issued 4/30/21. The upgrade work is not further described.

Unit 1008 and 211. 1008 had roughly 1.75" additional tile, where 211 had close to 3", as it was above the lower rail of the balcony rail, which was installed with a 2" spacing.

 

[gonefishing2]

Makes you wonder if slabs were already deflecting to the point that had to float thickset just to level floors. Great solution to sagging floor.

 

[MaudSTL]

In her first interview, she makes no mention of a noise like a wall collapse; describing the sounds as “construction knocks” or “renovation noises.”

https://collive.com/mother-escaped-with-children-r...

Yeah, I was somewhat discounting that piece because it was so sanitized for the religious community. For example, we know from multiple sources that the kids were both awake (Gabe cooking salmon, Chani taking a shower) and not asleep. So I have felt that source was less reliable than the CNN interview where Sara Nir is very specific about hearing the "wall collapsing" at 1:10 am. Maybe I'm wrong...

 

[MaudSTL]

Unit 1008 and 211. 1008 had roughly 1.75" additional tile, where 211 had close to 3", as it was above the lower rail of the balcony rail, which was installed with a 2" spacing.

Thanks! Are these the only two units with that amount of topping? Is the source the 2018 MC assessment?

 

[Demented]

Could have even been just tile being added over tile for the sake of changing the tile every few years.


Not sure if this has been linked yet.

https://www.youtube.com/watch?v=Ltw77weRymA

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

 

[Demented]

Thanks! Are these the only two units with that amount of topping? Is the source the 2018 MC assessment?

With that amount, yes. The only two, no. Source is 2018 MC assessment as well as personal knowledge of the balcony railing job that was to be completed with the renovations. Field dimensions were to be verified after balcony work began because there was some inconsistencies in the as builts vs the drawn, and decisions needed to be made over filling existing core holes and using base plates with 1/4" x 2-3/4" 308L stainless tapcons (because rusting stainless on the beach is better somehow) or using existing core holes. Over the years there has been at least 100 unpermitted renovations to the balcony surfaces. Home Depot sells all the stuff you need.


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

 

[Murph 9000]

… but there isn't any evidence the alarm ever sounded in the building. If it had, 6 minutes pre-collapse would have been plenty of time to wake people up and get them out.

I have a theory that I truly hope is wrong, and zero evidence to say it happened. Some fire systems are setup with a short delay before they go into full alarm, and it's been known in places like hotels for the guard or night receptionist to have a habit of cancelling the alarm and investigating, to avoid false alarms disturbing guests. It's a terrible habit that comes from frequent false alarms and bad decisions.

Another theory, is that some alarms don't go into full alarm from a single automatic detector or zone wiring fault, only with a manual pull point or multiple automatics. Some do a soft PA alarm to alert staff on the first stage, such as British railway stations paging "Inspector Sands" to the control room or office. The elevators might still recall on that type of alarm, until cancelled.