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

[Seppe]

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Previous thread (Part 06)
[link ]

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

[/url]

 

[SFCharlie]

Zoom in, see for yourself.

So where's waldo, ups, I mean the tar kettle? Forgive me for being old with bad eyes, but I've been scanning and scanning the high res you provided, and not coming up with anything?
Thanks

SF Charlie
Eng-Tips.com Forum Policies

 

[Nukeman948]

Yes, I had been thinking the same of the tar kettle, but how did they remain uncrushed as the black car is flattened? Did the material they were on cushion the blow, or were they on the pool deck already?

When I look at that picture of the flattened black car and tar buggy I see debris UNDER the car. I don't think those items are exactly where they were immediately after the collapse.
Once again, a picture without CONTEXT tells us nothing.

STOP posting pictures without Context and making up stories to fit you bias and stop trying to get me to believe your nonsense.

(that last sentence was not directed at you, SFCharlie)

Edit to add: I've worked construction for 35 years and have seen tar buggies and all sorts of other construction equipment parked in parking garages just like this one and that one MAY have been parked close to where it is in that picture. There were large voids in the collapsed area near the pool and the retaining wall. (Now I'm just speculating without context.)

 

[Optical98]

SF Charlie,

The reference from Nukeman (aka Roofing Contractor's Ins agent)was that the roofing items may have been on the "still standing" roof prior to demo. My thought was that there are ample photos of said roof, so I added the pic. But it doesn't transfer over to this site well enough to zoom in as clearly as I can see it on my compy.

My point was that the items are not seen on the roof prior, however there were some smaller kettles up there. I am curious as to where the larger kettle was found, I don't think it was on the roof btw.

Below zoomed in on small kettles -

 

[Optical98]

Nukeman you seem highly emotional and overly reactive to a calm discussion here..

 

[Nukeman948]

Nukeman you seem highly emotional and overly reactive to a calm discussion here..

LOL

EDIT: you called me the roofing company's insurance agent? And you think I'M the one that's getting emotional? LOL

 

[Optical98]

But I'm not speculating about the complaint from unit 302 Nukeman, it's contained in the documents. I will find it and add it to give you more CONTEXT.

 

[AusG]

re the flattening, it might have been parked up off to the side somewhere and not taken the full force of a descending slab. The cars are mashed to just over knee height by the looks, so that does leave some space.
also, been meaning to ask you guys...are these briefly-appearing spines the columns peeling out between the first and second collapsing sections of building? They appear at 03/25 of the CCTV and seem to me to be emerging between those two sections before rotating forwards and falling. If so they are already higher than the roof of the first falling section and give a visual guide to how much it had settled before the video starts.

https://res.cloudinary.com/engineering-com/image/upload/v1626664616/tips/image_uqalin.png

]

 

[Lizard7709]

Optical98 (Computer)19 Jul 21 00:19
Miriam Notkin and her husband from Unit 302, filed a complaint to the Town of Surfside regarding the horrible odors from the roofing operation, she wrote about the crane and kettle being very close to the building.

Link
In chrome translate to english..

Nicolás Vazquez "The smoke, dust, and " unbearable weird smell " also prevented them from breathing normally."

Can tar kettles catch on fire if unattended?

I was looking at this earlier. I was wondering if the crane to move the stuff on the roof and other heavy equipment was sitting on the road or on the deck that makes up the roof of the garage. There was an account more of the roof work in the HOA letters on the Town floor of Surfside website.

https://surfside.one/public-records-search/

Reading through everything I’m leaning towards the pool deck being the start of the failure. The 2018 report notes that there were repairs on the slab and that the cracks were continuing on from the repairs. To me this signals that the slab may overloading and previous repairs did not address the root of the problem. It also notes that the areas under the planters as being noticeably worse then the other areas.

I feel like it was only a matter of time for the slab to fail. I feel like a major part of it was the water deteriorating the strength of the concrete.

 

[Vance Wiley]

With no comment on what triggered this collapse, I think many here would agree that the effects of deterioration from a costal environment had reduced the reserve capacity of this structure. To what extent is yet to be determined.
So that brings me to the question - are there any FDOT structures in a similar environment that have survived 40 years? Have they required significant repairs and/or restoration in that timeframe? This is a serious question - I have not worked in a costal environment and would appreciate comments. Perhaps buildings should be designed, detailed, and constructed like traffic structures in coastal areas.
I would suspect the FDOT structures are inspected on a routine basis, perhaps something less than 40 years.
I will await test results of cores of the pool deck/plaza slab taken near the columns supporting that deck. The quality of the concrete at the time of collapse may be less than assumed in the design.
The results of core tests of the slabs near interior columns may shed light on what appears to be something other than failure in diagonal tension.

 

[Optical98]

The Crane and Kettle were on 88th street:

 

[jimstructures]

Optical98

Yes tar kettles can catch on fire whether tended or not. It has been 51 years since I tended a roofing tar kettle, but they catch on fire very easily.

Jim

 

[rodface]

https://youtu.be/HPwJ0JvTcg8

A simulation of the collapse has been
posted to youtube. Description text reproduced here for discussion:

================
Published on Jul 17, 2021
On the 24th of June 2021 at night, the Champlain Towers South, a 12-story beachfront condominium in the Miami suburb of Surfside, Florida collapsed partially. This collapse simulation was made based on the presently available data, eyewitness, and video accounts.

The authors are independent researchers and impartial hoping to constructively contribute to the fact-finding. This study demonstrates the collapse mechanism assuming the following plausible hypothesis:

According to the data, the basement deck showed signs of extended soaking for many years. The problem was locally insufficiently patched and not rectified in its entirety. The wetting caused the deck ceiling to be weakened to such an extent that basement pillars punched through the deck where additional load had peaked at the planter area.

The authors hope to not distress relatives of victims with the application of dummy dolls in this simulation that have the sole purpose of tracking victims in potential cavities within the debris.

The Bullet-Constraints-Builder simulation software is open-source, it was developed within the EU FP7 funded INACHUS framework.

Kostack Studio was supported by Architect Oliver Walter with the data analysis.

Main sources:

https://youtu.be/KR29pLccutY

8777-collins-avenue---preliminary-review-plans-for-40-year-re-certification.pdf
8777-collins-ave-1979-plans.pdf
8777-collins-ave---unverified-inspection-report.pdf

Credits:

Simulation & video by Kai Kostack

http://kostackstudio.de

Consultant: Dipl. Arch. ETH Oliver Walter

Music:
Sergey Cheremisinov - Fog (CC BY)
Kevin Hartnell - Aurora (CC BY)

Made with Blender + BCB + Fracture Modifier

https://blender.org

https://inachuslaurea.wordpress.com

https://blenderartists.org/forum/show...

The "BCB" structural simulation software has been developed at the Laurea University of Applied Sciences, Finland. Written within the scope of EU Inachus FP7 Project (607522): Technological and Methodological Solutions for Integrated Wide Area Situation Awareness and Survivor Localisation to Support Search and Rescue (USaR) Teams

 

[rodface]

Some frames of interest from the simulation:

The presumed origin of the collapse, with pool deck and building shown:

Same view with deck and building hidden, revealing structural members:

Bright red presumably highlights the elements that will fail (have not listened to the audio):

This closely approximates the initial frame of the CCTV film:

Center section has collapsed, still-standing eastern section begins to tilt westward:

Collapse of eastern section well underway:

Now stepping back in time:

This camera is the closest one to the Tiktok video that I could find. Someone else may be able to identify the columns. I believe the vertical yellow surface at left is the eastern stairwell shear wall; we are looking south-southeast as though parked in the northernmost row of the garage. The ramp should be obscuring our view to the left. I may be misinterpreting the view.

The pool deck has punched through and almost come to rest.

Some comments:
I am not sure I see the “step” in the slab that is shown on the drawings. Is this area modeled correctly?

The collapse progresses without delay in the simulation. I would love to know how much they had to fiddle to get it to look this close to the actual collapse, or if it readily produced this outcome given the model that was provided.

 

[Vance Wiley]

That is a well presented simulation. The view from the adjacent balcony gives it relativity to me.

In watching the video of the collapse at "Main sources:

https://youtu.be/KR29pLccutY

" I do not see any disturbance of the pool surface - the reflections appear stable to me. Bad eyesight?

 

[spinspecdrt]

The slab steps are in the model but they appear as beams when the slab is omitted to show the framing. Only the vertical portion of the step is shown. (In the shots that reveal the framing.)

I did notice the beam38's are missing from the east stairwell.

It's very interesting that they show some initial failure on the north side. Starting at about 4th floor down to lobby level. Makes me wonder what information that is based on.

 

[human909]

It's very interesting that they show some initial failure on the north side. Starting at about 4th floor down to lobby level. Makes me wonder what information that is based on.

I wouldn't discount the possibility that limited analysis of root cause was done in producing this model. Working out which column likely failed first isn't the hard part. Working out WHY they failed is. And although it is a very impressive model this is a model of HOW not WHY.

 

[MaudSTL]

It's very interesting that they show some initial failure on the north side. Starting at about 4th floor down to lobby level. Makes me wonder what information that is based on.

I was reviewing witness statements today, and discovered several details I had previously missed that could be related…but nothing specific to the fourth floor.

Remember that Gabe Nir has stated in multiple interviews that there were three stages to the collapse: Knocking noises and a crash from above, the deck collapse, and the building collapse. “Gavriel Nir tells the network that the collapse occurred in three stages and took a few minutes. First, he and his family heard noise from above and saw dust falling. They then heard a boom that they thought was an earthquake and rushed out of the building. Finally, from outside, they saw the collapse, with white clouds of dust following them as they ran.” Times of Israel

After the first collapse described by the Nirs in 111 as sounding like a wall collapsing in the apartment above them, both Gabe and Chani mentioned that they saw “dust falling” (Gabe) and “white particles” (Chani.) This seems to support the possibility that they really did hear a crash from above, as they all have described, instead of from below. They would have seen the falling dust between 1:10 am, when they heard the first collapse, and 1:15 am, when Sara Nir was in the lobby complaining about the “construction sounds” that they were hearing and then the deck collapsed. In one feature that quotes Gabe, he also says that dust started blowing into 111 from the patio, and he felt “the ground was shaking.” This new simulation depicts the deck collapse starting in the garage and expanding out to the deck, which would be compatible with how Gabe describes what happened between the first collapse and the deck collapse.

By 1:15 am, Gabe and Chani were standing in the doorway of 111, and ran to the lobby to join their mother as the Vazquezes were getting off the elevator. So nobody was still inside 111 as the deck collapsed.

I also found some new information that is interesting. There now may be a third driver who was in the garage right before the collapse: Sara Nir. Apparently, she was at an activity with her religious community, and Gabe was at the gym working out. Sara picked Gabe up at the gym on the way home. They arrived home to 111 at 12:30. The article does not state explicitly that they parked in the garage. But if they did, we now have three vehicles with survivors who have not mentioned any damage in the garage immediately prior to the collapse:
[ul]
[li]Eric and Tamar Zion(at about 10:30, 11:30, and 12:30) [/li]
[li]Sara Nir and Gabe Nir (at around 12:20 or so) [/li]
[li]Nicolas Vazquez and Gemina Accardi (at about 1:00-1:10) [/li]
[/ul]

 

[MaudSTL]

 

[AusG]

Interesting that their very first visible movement is a rotation inwards and falling away of some facade panels on the ground floor. I guess the unvisualised beam failures below them freed them up to fall.

The deck slab fails inside the footprint of the building next, the pool deck columns are just starting to punch at that stage. I think they have moved the locus of first failure a half-span north from most analyses here.

 

[1503-44]

Nice picture, but the building clearly fell in three (3) parts, that shows two. There is probably little to no real physical accuracy there.