Miami Beach, Champlain Towers South apartment building collapse, Part 04 49

[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

SF Charlie
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[Mark R]

Reinforcing shop drawings sequence:...
Some place in this sequence, rebar mill certificates are submitted for approval.
It is the rebar detailer that solves the placement problems - this shouldn't be done in the field.

This is the sequence I'm familiar with, sometimes depending on the complexity of the job certain steps or jumped over, quite often the shop drawings are not reviewed in-house or not reviewed by the contractor or not by the EOR if it's a very simple project. Always at least 1 of those 3 levels review the drawings but quite often not all 3 of them. I've seen in many cases that the EOR is the only reviewer and in some cases where it's only SOG are strip footings it will be the contractor instead of the EOR. Normally from what I've seen these days the mail certificates are required more often than not also the mixed specifications from the concrete plant are required to be submitted in most cases. Of course, test cylinders are always taken in the field too.

 

[DavPc]

Historical video footage of the crane collapse from 1980 during the South Tower construction:

https://www.youtube.com/watch?v=GJ9Jt1zPDMA

After taking note of:

- Where the Bluegreen Hotel is in these shots,
- The former parking lot where the crane was stationed,
- The location of the central core stairwell in the Polaroids

it appears the boom fell NE across the 2nd floor of SE corner of the tower and over onto the pool deck.

None of the concrete appears to have been poured yet for this area (other than the columns) so damage to the deck concrete all these years later would not be a factor. But how the boom parallels the fault line of the deck collapse is downright spooky and perhaps some of the forms or rebar was damaged - but not badly enough to warrant reinstallation?

Also if nothing else it is interesting to see the earliest footage thus far of how the rebar in this part of the building was installed.

 

[JohnRBaker]

The Miami-Dade Country fire authority, who it seems is officially responsibly for the rescue effort, has notified the families still waiting for word on their loved-ones, that the rescue effort has now been officially moved to a status of recovery:

Search of collapsed South Florida condo shifts from rescue to recovery

No one has been pulled out alive since the first hours after the 12-story building fell on June 24.

https://www.tampabay.com/news/flori...florida-condo-shifts-from-rescue-to-recovery/

John R. Baker, P.E. (ret)
EX-'Product Evangelist'
Irvine, CA
Siemens PLM:
UG/NX Museum:

The secret of life is not finding someone to live with
It's finding someone you can't live without

 

[Vance Wiley]

A great sequence and program.
My main complaint was the General Contractor simply stamped the submittal to date it and put it in the out box.
Very little help from the contractor at that stage.
So if the EOR gets a submittal stamped by the General Contractor it COULD be considered a request to build it that way. If that meets the intent, the EOR COULD stamp it and - - is it the Contractor's responsibility after that?
Points for consideration at the court proceedings, I guess.

 

[1503-44]

"There's

http://www.almadepiel

.com, but otherwise I am not aware of it as an idiom."
That

http://www is

an advertisement for a leather "piel" handbag design studio.
Its also the title od an old song by Tito Rodriguez.

 

[IEGeezer]

I couldn't find Alma de Piel by Tito Rodriguez. Instead I found:

La piel de tu alma by Tito Rodriguez & Louie Ramirez (

https://www.youtube.com/watch?v=PP4JRD25GVw)

While I was at it, do you remember:

Eydie Gormé and Trio Los Panchos - Piel Canela, Sabor A Mi, Granada (1964) LIVE (

https://www.youtube.com/watch?v=kQeGLk4nGus)

And finally, do you remember the unforgettable coloratura soprano:

Xiomara Alfaro - Siboney (Hi-Fi Audio) De Ernesto Lecuona - 1957 ¡Ole Cuba! Film (

https://www.youtube.com/watch?v=20wj3xS-6qg)

With a voice like that, maybe somebody was playing a recording of her and that may be a factor in the collapse.

 

[jbourne8]

I don't have any opinions on what the trigger was, but after reading through all of these threads a few bits of info haven't been mentioned yet.

In one of the permits dated 5/17/2021 they did some roof core testing and found a lot of "water affected roof materials."

You can see them graph this out on the map as well in the permit. Kind of makes you wonder if this is the "curious" thing he found.. although, it doesn't seem that curious to me. It is the one thing he actually documents about the concrete that seems like it'd fit though.

These are both from this permit -

https://www.townofsurfsidefl.gov/do...-records/8777-collins-ave-permit-2021-211.pdf

It just seems odd that all they did was re-tar the roof before sticking a roof anchor right into the most effected spot on that map, only a month later. They mention ponding on the roof, and it looks like it's probably draining into the building right where that column is. Also, in a 3/3/1994 electrical inspection on the building they have a note that says "MIDDLE ROOF FACING SOUTH AND HIGHEST LEVEL OF ROOF NOT FINISHED" but there's no real info on when it was finished or what wasn't finished exactly.

At least two of the roof anchors were never installed, P21 and P23. Makes you wonder if they stopped for a reason, since they were already up there and mounted two of them in that spot.

You can see them missing on the right side of the highest spot of the building. I actually had to check the google satellite view too, but there were no pieces of that section of roof that fell.. so they must have not installed them.

In this article they also have an interesting photo near the very end -

https://www.washingtonpost.com/nation/interactive/2021/victims-survivors-surfside-condo-collapse/

(It's behind a paywall, but if you use an incognito window to load it it'll let you read it even if you've reached your max articles.)

It's taken from 409 and shows some broken up tile behind one of the planters that's probably over a column (the one that's between parking spots 24 and 31 and doesn't seem like it as part of the collapse), but mostly it makes it really clear the sort of view that Cassondra had when she called her husband. Seems like she would have seen the patio to 111 pretty easily, or anything falling from the roof.

Also, I also dug up an old photo of the garage on google street view and lightened it, and I think it's pretty clear that we would be able to see the column in the tiktok video if it was still standing.. and it confirms that it's exactly where those rectangular pieces are in that video. It's hard to see in this pic, but there's definitely a light spot where it is on the plans. If a car did hit this column too, we wouldn't be able to see it's license plates on the other side of the standing column. Perhaps it's obvious that it's missing, but I was a bit curious if the old plans even matched the basement column layout.

 

[gonefishing2]

I found this video interesting, even if it is not the trigger....

Link:

https://www.youtube.com/watch?v=383SIaQDg0k

 

[jbourne8]

This has a lot of good historical information on the three condo towers -

https://www.miamiherald.com/news/local/community/miami-dade/miami-beach/article252467273.html

According to property records, the lady that sued them in 2001 and 2015 for water damage owned 112.

 

[Js5180]

jbourne - could anchors 21 and 23 have been cancelled, due to that portion of the building being cantilevered in a sense? It seems like they completed the roof tar without the anchors, suggesting they had decided against doing them.

Alternatively, the plan appears to show a north-south wall in the middle of the machine room roof. Is it possible that the contractor read the plan, and assumed 21 and 23 were not located on the uppermost roof?

Also, note that eastern edge of the 12th floor roof, over x10, is very wet. That area butts up against the penthouse wall. That is also directly over where the collapse appears to have started.

Hypothetical question for those with a physics background:

First, is it correct to say that a free-fall from the highest level, absent significant air resistance, would proceed as 32 ft/sec after 1 sec, 64 ft/sec after 2s, and 96 ft/sec after 3s? And the cumulative distance would be 16, 48, and 128 feet after each second, meaning that the FASTEST the building could collapse would be roughly 3 seconds?

Second, if the video was of sufficient resolution, and the speed of a falling object in the video could be estimated... couldn't that also tell us when the free fall started?

For example, if the video starts with a particular unit falling at 64 ft/sec, then the collapse could have started no later than 2 seconds earlier?

Just wondering if more details of the second or two before the video starts could be calculated based on the speeds of objects in the first few frames - especially if we saw two different sections moving at different speeds.

 

[kjm93]

Js5180 - the free-fall distance at any time “t” would be d=16.1t^2 and velocity would be v=32.2t.

 

[SFCharlie]

is it correct to say that a free-fall from the highest level, absent significant air resistance, would proceed as 32 ft/sec after 1 sec, 64 ft/sec after 2s, and 96 ft/sec after 3s? And the cumulative distance would be 16, 48, and 128 feet after each second, meaning that the FASTEST the building could collapse would be roughly 3 seconds

I get 32 ft/sec after 1 sec, 64 ft/sec after 2s, and 96 ft/sec after 3s? And the cumulative distance would be 16, 64, and 144 feet after each second, meaning that the FASTEST the building could collapse would be roughly 3 seconds
I don't think this changes your argument in any way
I'm sorry, but the video is too dark and fuzzy for me to measure all this. (I did a lot of work on the FIU bridge dash cam, which was much better quality. when you zoom in on a single frame, a lot of the definition your eye/brain "sees" from interpolating different frames, goes away.

how-to-calculate-time-and-distance-from-acceleration-and-velocity

SF Charlie
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[Js5180]

Thank you Charlie. The resolution seems like a major impediment for this to work.

JBourne,

I found an alternate diagram for the machine room roof which does not have the dividing wall:

Also, the last column showing in your 2015 streetview is the one on the northwest corner of parking spot 27. That is the same one standing in the tiktok, with the white top and yellow bottom. In the floor plan below, I've put a purple rectangle around it.

The next column, based on the perspective, should be in the red rectangle in the image below. It's not visible, but it doesn't appear to have ever been visible in a photograph. The one after that would be in the orange. It's also not visible.

However, the orange column was still standing after the collapse:

(photo: WSJ)

I'm inclined to think that at least some of the red column should still be visible in the tiktok video, while the orange one clearly is not. That makes me think that the red column went down completely. Arguably, there is debris leaning against the orange column in the tiktok video.

 

[jbourne8]

Js5180,

Ah yea, that's a better diagram. Still a bit odd that they're missing. Perhaps that's just where the stopped for the day.

And you might need to zoom in a bit on the street view pic I posted, but I do think there's a lighter spot that shows the red column between 27 and 28. It's pretty hard to see, and mostly just visible near the top of the pic. I couldn't find any better pics though, it seems like the garage lights are too dim during the day to see in that far.

It is sort of odd we can't clearly see that orange column #28 in the tiktok video too, if the deck was completely collapsed then. Seems like the slab must still be connected to the building, and that could be blocking the view to it.

 

[Js5180]

Quick question - how do you get historical street view images?

 

[jbourne8]

Js5180 - Yea.. I think it is a lot easier to see on the google image itself. When looking at a building on street view, there's a small clock right next to where it says street view, in the grey box in the upper left. You can actually see it in my pic, but that part's expanded there. Sometimes you have to click around a bit though on the street before you'll see that pic as an option though, I think I had to go to 2015 pics at the end of that road before I could get to that exact spot.

 

[apper.42]

I think that I have read every serious post and either missed or no-one has posted information or asked about destructive tests that were recently made from typical cores taken from the pool deck, roof, balconies. Also there is no comment from anyone if there are construction records, shop drawing approvals, materials testing from the original construction. For liability purposes most firm and municipalities file this information.

APPER.42 Peng. Retired

 

[Illustr8r]

La alma de piel is like the ‘soul of the place’ or ‘the bones’ one would take it like the soul of the building and deeper than the bones

 

[jbourne8]

apper.42,

The recent ones don't seem to be online anywhere, but there are some old concrete tests from 2002 buried in this old permit -

https://www.townofsurfsidefl.gov/do...s-repairs-concrete-restorations-balconies.pdf

Although, these seem to be from concrete they were pouring back in 2002 for repairs on balconies and the south wall by the pool. It does seem to say they tested it beforehand, but the results don't seem to be included. I know nothing about concrete, but with mortar you have to test the mortar first so you can make a close match or it won't adhere correctly. It seems like if they're aiming for a slump of 5 or 9, that's probably what they got back when they tested it?

Page 33:

Page 81:

That's all the info too btw, nothings on the bottom of those pages. There's also a curious note on page 15 of that permit about 204 having an uneven slab.

 

[1503-44]

That Eydie Gormé link has several classics. The Steve Allan Show. I was 7 or 8yrs, but I do remember that. Solamente Tu. Singer at my Colombia hotel bar liked that one. Dios mio. 03:24 Granada. Saludos desde Canarias.