Miami Beach, Champlain Towers South apartment building collapse, Part 18 30

[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
Miami Beach, Champlain Towers South apartment building collapse, Part 11
Miami Beach, Champlain Towers South apartment building collapse, Part 12
Miami Beach, Champlain Towers South apartment building collapse, Part 13
Miami Beach, Champlain Towers South apartment building collapse, Part 14
Miami Beach, Champlain Towers South apartment building collapse, Part 15
Miami Beach, Champlain Towers South apartment building collapse, Part 16
Miami Beach, Champlain Towers South apartment building collapse, Part 17


SF Charlie
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[hokie66]

If that slab drop detail is in bending transverse to the 12" upstand, it makes for quite a good hinge.

 

[Reverse_Bias]

BMA's are only 5 1/2" deeper than the slab at line 11.1 and could have been nested between the column/slab connection rebar. In the recovered specimen, it looks like the end that rested on line 11.1 (the far end in the image) is void of concrete which allowed it to slip off the column support. If so, the surviving column presents as expected.

Thanks for the clarification. Seems like most of the rebar would have been in no mans land where the beam, column, and slab met. If that part of the concrete cracked away when the slab dropped there would have been little room left for the bottom of the beam to maintain connection.

Hopefully the NIST presentation will provide more detail on these connections since they are critical to the collapse and preventing similar disasters.

 

[SFCharlie]

Great discussion. One of the best!

SF Charlie
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[dik]

new stuff...

https://www.npr.org/2023/05/31/1179...a-condominium-collapse-champlain-towers-south

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[Jeff Ostroff]

If you guys are following the Davenport collapse, last night (Wednesday at 7 PM EDT) the City of Davenport unleased a treasure trove of info similar to what Surfside did on their building department website.

Lots of violations, and photos 3 years before showing a building crying out for help. I just uploaded my root cause video based on before and after photos. So many parallels with the Davenport building collapse with the Champlain Towers south in terms of neglect and stupidity and going against engineers recommendations..

 

[SFCharlie]

If you guys are following the Davenport collapse

Please post this on the Davenport thread...(Davenport) Apartment Building Collapse
The folks there will want to know...
Thanks

SF Charlie
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[MaudSTL]

Allyn Kilsheimer responds to an Iowa reporter.

https://www.kcrg.com/video/2023/06/...ineer-weighs-in-davenport-apartment-collapse/

 

[IEGeezer]

With regard to the pool deck punching failure, WJE suggested that using a coefficient of 3 instead of 4 may be better when considering critical shear crack theory:

I found an article titled "Addressing Punching Failure" that supports WJE's point. I am uploading it.

 

[MaudSTL]

Tomorrow is the NIST meeting that will include their initial failure theory. ABC News published a piece on the proposed new building that includes a video retrospective that adds nothing of substance.

New condo tower could be built at site of Surfside condo collapse

 

[MaudSTL]

Very early in their overview, NIST stated that they have to date found no CTS security cam equipment/videos.

Effort to date:

They explain the involvement of MDPD investigation as a “death investigation that could become a criminal investigation.”

The agenda has been updated with links to the presentations.

https://www.nist.gov/topics/disaste...-safety-team-ncst/advisory-committee-meetings

In the Concluding Remarks presentation, I t appears they are looking at K13.1 and the planter as the initial point of failure. Let’s see what Glenn Bell has to say when he does his presentation.

https://www.nist.gov/system/files/d...06/14/14_CTS_Conclusion_BELL_NCSTAC_final.pdf

 

[Sym P. le]

Toddlers can draw!

Previously posted by aspiring investigator

The difference a year can make

 

[stcbus]

So ridiculous no security cam footage and no explanation still for no fire logs? Supposedly all of that was in that part was was still standing until they decided when/how to demolish it...

I think the condo rep who was TOLD via e-mail to grab the fire control panel should be under criminal investigation.

 

[MaudSTL]

Here’s the NYT’s story on the meeting that is currently in progress.

https://archive.ph/8Ep1W

 

[Murph 9000]

So ridiculous no security cam footage and no explanation still for no fire logs? Supposedly all of that was in that part was was still standing until they decided when/how to demolish it...

I think the condo rep who was TOLD via e-mail to grab the fire control panel should be under criminal investigation.

It's possible that the security recorders were legitimately too risky to recover. On original plans, there's a security closet immediately north of the lift shafts. In the 2021 state of the lobby, the door into that was on the north side, into what I believe was the mailbox room (i.e. not directly into the lobby, as per the original plans). The lobby floor slab had failed in that general area, based on the video of firefighters drilling into the collapse zone from the car park below the lobby. Putting that all together, if the recorders were in that closet, it's quite possible that it was too dangerous (or even impossible) to retrieve them. I don't know for certain that the security recorders were there, it's just a likely location for them.

As for the fire panel, it's clear that was behind the front desk and should have been recoverable. The responsibility for retrieving it, however, shouldn't have been with the "condo rep"; but with PD, FD, or NIST.

 

[SFCharlie]

Curiously, some of the best info is the the conclusions?
Concluding Remarks and Next Steps
Also see slide 6 in the following presentation:

Cross-Project Panel Theme 2:
Materials, Geotechnical, and Structural
Analysis and Testing

SF Charlie
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[stcbus]

It's possible that the security recorders were legitimately too risky to recover. On original plans, there's a security closet immediately north of the lift shafts. In the 2021 state of the lobby, the door into that was on the north side, into what I believe was the mailbox room (i.e. not directly into the lobby, as per the original plans). The lobby floor slab had failed in that general area, based on the video of firefighters drilling into the collapse zone from the car park below the lobby. Putting that all together, if the recorders were in that closet, it's quite possible that it was too dangerous (or even impossible) to retrieve them. I don't know for certain that the security recorders were there, it's just a likely location for them.

That is interesting, but if they are were all in the building retrieving animals and searching for people, under the structure in the garage, someone can't go in there quickly and take a look? Or set up some temporary support?

As for the fire panel, it's clear that was behind the front desk and should have been recoverable. The responsibility for retrieving it, however, shouldn't have been with the "condo rep"; but with PD, FD, or NIST.

Maybe, but did the condo rep communicate to anyone about it? According to the e-mails, the original company owner who installed the system even volunteered to go get it.

Side note, is it just me or does quoting suck and is completely manual here? I am used to proper forum systems with real quoting abilities. I feel an "engineering" forum should have a bit better forum system.

 

[SwinnyGG]

I feel an "engineering" forum should have a bit better forum system.

Note that software engineering sections of this forum are some of the least active

Turns out civil and structural engineers don't care much about software UE

 

[stcbus]

Note that software engineering sections of this forum are some of the least active

Turns out civil and structural engineers don't care much about software UE

Hmm, I like everything I produce or use to be well designed. Maybe that's just me.

 

[IEGeezer]

It's possible that the security recorders were legitimately too risky to recover. On original plans, there's a security closet immediately north of the lift shafts. In the 2021 state of the lobby, the door into that was on the north side, into what I believe was the mailbox room (i.e. not directly into the lobby, as per the original plans). The lobby floor slab had failed in that general area, based on the video of firefighters drilling into the collapse zone from the car park below the lobby. Putting that all together, if the recorders were in that closet, it's quite possible that it was too dangerous (or even impossible) to retrieve them. I don't know for certain that the security recorders were there, it's just a likely location for them.

I think that is the collapse of the NW entrance ramp. A screenshot of what I believe was that video is placed next to an image of the parking spaces from the NIST presentation and shown below. The image from the video is from the vicinity of parking space 96 showing parking space 110 marked on column A5, I believe:

Here's the video:

https://www.youtube.com/watch?v=MmleL6I2T5M

 

[Murph 9000]

I think that is the collapse of the NW entrance ramp. A screenshot of what I believe was that video is placed next to an image of the parking spaces from the NIST presentation and shown below. The image from the video is from the vicinity of parking space 96 showing parking space 110 marked on column A5, I believe:

It's not the NW vehicle ramp for the main entrance. The key identifier for me in that video is right at the start. There's a double column which can only be A2 and B2. Column A5, in front of them, is visible at the start of the video, but behind the main action. The main group of firefighters who are drilling are stood between D2 and D5, trying to drill eastwards at roughly column E4 (into approximately the east-west corridor). The E columns were where the collapse progression stopped north of the elevator shear wall, but evidently the lobby slab had fallen at that point, and you can see that there are several other slabs on the D-E bay which look like they are sagging in the surviving section of the tower. (Page 30, basement level framing plan, of the big PDF of original plans is a good one for the above.)