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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[SFCharlie]

NIST may have done a deal with MDPD to maintain the chain of custody?

SF Charlie
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[Jeff Ostroff]

The 60 minutes video I saw was only 13 minutes. I that all there was, or was there a full hour broadcast?

 

[Jeff Ostroff]

Channel 6 story here in Miami from last week, the story here in Miami about another apartment collapse yesterday it was a small one nobody got hurt but during the investigation channel six has uncovered the fact that the building was approved by a city engineer and has his stamp on it, only problem is he died long before the building was approved and now they don't even know if anybody even inspected it period now channel 6 is uncovering other buildings that have his stamp on it even though he was long since dead.

"Questions Remain Over Who Approved Hialeah Building That Partially Collapsed"

https://www.nbcmiami.com/news/local...ah-building-that-partially-collapsed/2897925/

 

[JohnRBaker]

Apparently the voters in Miami have taken it upon themselves to help mitigate this sort of thing happening again:

Major Miami Beach Real-Estate Projects Nixed by Voters

Residents voted against referendums that would have allowed Related, Starwood and Peebles to develop on the beach

https://www.wsj.com/articles/major-miami-beach-real-estate-projects-nixed-by-voters-11668381400

John R. Baker, P.E. (ret)
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

 

[MaudSTL]

Just ran into a CBS piece from Jan. 11, in which Allyn Kilsheimer says his firm is 90% sure that geology was not a factor. He is still trying to gain access to the materials for testing. NIST is apparently still blocking him.

Expert 90% sure geological conditions did not cause Surfside condo collapse

 

[jorton]

It is interesting to see how the market is responding. It seems that an open database rather than secret blacklist would provide excellent incentive to properly manage and maintain property.

https://www.bisnow.com/national/new...&utm_content=outbound_link_2&utm_medium=email

 

[Sym P. le]

I'm quite sure geology will not be found to be a factor and money has a way of leveling the field. It's a shame these folks weren't able to capitalize their assets rather than losing them. The footprint value of the property was astounding but now that there is a rush to secure numerous additional properties, the ability to cash in is much reduced.

The state of decay of the lobby parking deck (for years) is so obvious (at least in hindsight), it should be embarrassing. Given the witness accounts of collapse initiation in the lobby parking and prior documented failure of two pool deck slab/support column connections it is really only a matter of scouting out the final straw. I might see one, the rebar stub below stall 135 and missing lower rebar mat.

Edit: Also, a well considered structural analysis at Eastern Engineering Group: Champlain Towers Collapse Structural Analysis Revised, by Ernesto F. Valdes,October 25, 2021

Crosseye stereo views of lobby parking (previously posted)

 

[zebraso]

I might see one, the rebar stub below stall 135 and missing lower rebar mat.

It is something how some time away from this makes some things stand out slightly differently. To think about progressive collapse in this repetitive punch through at the parking/pool deck area seems almost too much. These were primed to go IMO as a unit IMO. So if you take that factor out, and say only one of these columns at the parking deck actually had insufficient mat, then does the building ever collapse? Was that one point the trigger? does that even matter? If you have a gas leak as an analogy in a building and the gas has reached explosive concentration. How important is it to identify which of a dozen or so possible ignition points were at fault? This contactor or that light switch? How many of those green arrows can you make if you really try? I should think there has to be something that allows this pool and parking deck to collapse without the result being that the building went with it, assuming it did not start at the corner of the gym. But yeah the parking deck seems to have collapsed before the building. So was the designer thinking "they better take care of the pools deck or else"? If he could say that today would it be shocking?

 

[Sym P. le]

Three indicators became visible over time, the lobby parking slab cracks, column 76, and the planter column. The fourth, as I've indicated, was hidden. The rebar at stall 135 is more sparse than column 72/73 (it appears the last strand snapped) and provides a plausible conclusion to the evidence which fits with everything else that is known. It should help to focus the discussion. Unfortunately, the parking slab cracks were seen for their nuisance of water dripping on cars and the column connections for that uneasy queasy feeling they gave. Perhaps in the future, these inconveniences will lead to proactive precautions and remedies before the hidden factor bites anyone in the assets. Parking and pool parties should have been suspended.

It only takes one green arrow, the rest can be copied and pasted.

 

[zebraso]

before the hidden factor bites anyone in the assets

Yes. That's just it. Hidden, and hidden from whom? And how much willful blindness does it take? How does this mindset manifest itself? How many parties have to be involved and at what levels?

 

[Sym P. le]

I'm not into conspiracy theories, nor do I subscribe to ignoring evidence. No one ran from the gym exclaiming "The gym is falling!". A witness did run from the lobby (past the gym) to collect their family when they saw the lobby parking collapse. When various pieces of the puzzle are turned over, it is actually possible to put the puzzle together.

 

[zebraso]

I don't think it takes a grand conspiracy either. But there is a sort of pathology and rationalization for neglect that is its own puzzlement.

 

[SFCharlie]

Thanks for the photos and the link to the article!

SF Charlie
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[Sym P. le]

If we're talking about the years of neglect, of course. If we're talking about ferreting out another puzzle piece, the rebar stub or two (single lower mat strand on column center line) are also relevant. Everyone can see that the rebar is sparse but no one has noted that there is even less under stall 135. To me, it provides additional weight to the collapse fact pattern.

P.S. Regarding pathology, the slab cracks were dutifully repaired though apparently to reduce the nuisance of leaks. I'm not sure anyone can pretend that epoxy would restore structural integrity but it seems that was part of the rational for the effort. In fact, the extensive slab cracks were more than a canary in a coal mine, they were a waving red flag to the lack of fitness for service. Once I woke up to that reality, it helped to put the rest of the issues in context.

 

[SFCharlie]

reading the article from the post -(Sym P. le (Mechanical)18 Apr 23 18:36
Eastern Engineering Group: Champlain Towers Collapse Structural Analysis Revised, by Ernesto F. Valdes, October 25, 2021)
FIG. 3 PARKING LOT SLAB FAILURE PROCESS DUE TO CORROSION
Looks a lot like the pencil point top of the columns as noted by many on the thread.
[URL unfurl="true"]https://res.cloudinary.com/engineering-com/image/upload/v1682100605/tips/FIG._3_PARKING_LOT_SLAB_FAILURE_PROCESS_DUE_TO_CORROSION_sjypat.webp[/url]

SF Charlie
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[Sym P. le]

I like the idea that we have an explanation for the pencil tips but I think the upper mat merely glanced off the side of the columns which is effectively the same. Witness accounts point to sudden failure in the lobby parking with a progression through the remainder of the pool deck.

 

[zebraso]

I'm not sure anyone can pretend that epoxy would restore structural integrity

Yep. A pre-sheared or "missing" strip bar is part of a very deficient process and no drop panels either. What am I missing? I see "people" as noticing (news stories) the future of electric vehicle weight just might pose problems for aging parking decks. Is there an awakening here?

 

[SFCharlie]

I think the collapse of 57 Ann St. NY, NY, got the attention of a lot of the moneyed interests. A lot of pretty (and pretty expensive) cars got smashed.

SF Charlie
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[zebraso]

A lot of pretty (and pretty expensive) cars got smashed.

You have a very cutting sense of irony that I can really appreciate.....And you are quite correct IMO.

 

[zebraso]

Edit: Also, a well considered structural analysis at Eastern Engineering Group: Champlain Towers Collapse Structural Analysis Revised, by Ernesto F. Valdes,October 25, 2021

How much of the item one "A reinforced slab (topping) was added to the slab covering the parking lot with a welded wire mesh and paver.", was part of prior discussion here? I recall the discussion of the cores and identification of the topping layer. But I can't seem to recall the both direction of reinforcement were welded together. That's what the report you cited is saying, when it says the deck formed a "shell". And then primarily this shell being anchored at both n/s extremities is what caused the failure to progress to the building proper. I have seen the theories that run along these lines, saying the diaphragm action led to failure, or that somehow the deck was supporting the entire structure. But that is not what this report is saying. Is this view widely supported? I mean it basically makes sense to me. And it's from 2021.