Miami Beach, Champlain Towers South apartment building collapse, Part 15 32

[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

SF Charlie
Eng-Tips.com Forum Policies

 

[FJBnomics]

This reposted picture shows the different failures along South Wall between parking deck and patio deck from a different perspective. K-line being the dividing line between different phases of failure. Coupled with last image in IanCA's 6 Feb 22 06:30 post above:

 

[FJBnomics]

Here is the deleted post in which the poster has withheld their name.

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Current Post: Edited 08 Feb 22 12:35
Original Post: Posted 08 Feb 22 12:26
Nothing to see here. I just thought I'd check in to see how this thread was progressing. I was curious. I had nothing better to do so I did a quick review of the number of posts for the time period Feb 1-7. I didn't read any of them (who has the patience at this point), just added them up. Here are the results:

0.14 posts/day - NukeDude948, sgw1009, AusTony2046, spsalso, AutisticBez
0.29 posts/day - Reverse_Bias, AusG, SwinnyGG
0.43 posts/day - Jeff Ostroff
0.57 posts/day - Red Corona
0.71 posts/day - Lionel Hutz
1.00 posts/day - Optical98
1.29 posts/day - IEGeezer, Zebraso
1.86 posts/day - MaudSTL
3.71 posts/day - Sym P.Ie
4.00 posts/day - IanCA
5.86 posts/day - Thermopile

For a total of 139 posts/week => Extrapolating out to 7,228 posts/year

It's interesting--well, really not that interesting--but the two most prolific posters are names that are new to me. But are these really new people, or just the same ISP web address, but with a different user name? Who knows what the policy is for engineering.com.

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I for one, who love to sit and listen to a limited invite presentation from IanCA, IEGeezer and others on their theories as they have introduced some interesting thoughts and evidence evaluation, IMO. e.g. The re-posted image below with narrative. I think IanCA and IEGeezer have the most interesting theories going currently, based upon limited public evidence, and Sym P. le is a great rock thrower to force critical thinking and evaluation and discussion. However all theories must be considered at first and then go throw a manageable and creditable amount of rock to narrow candidates down for the SuperBowl Half Time Show.

Nuke.........948, I am editing this post to tell you that your earned a Star for your post directly after this one. I have used my one Post allotment Per Month today, so I will have to edit this post, because we are being watched by the ..............!

 

[Nukeman948]

Anything you post, can and will be used against you in a court of law...

[sub]Names have been changed to protect the innocent.[/sub]​

 

[Optical98]

Ahem...only "prolific" posts. Oh, wait where have I heard that term?

 

[Nukeman948]

Suddenly, when I click on the lawyer's "member profile", all I get is an error message.
Nice name change.

[sub]What is the purpose of rhetorical questions, anyway?[/sub]​

 

[zebraso]

I didn't read any of them

Yeah, no.

 

[FJBnomics]

Have we lost our ‘Rock Chucker’ since his name was recognized by ‘Mystery’ Poster, and he was associated with the likes of the folks on ‘Mystery’s’ Black List?

Edit:! Perhaps we need to call in the ‘Nuke’

Seriously, it is sad that the new analysis and piecing together of the long available evidence puzzle pieces was making progress, until a ‘Mystery’ poster with an counter agenda, has shut down the collaboration.

Clearly a public forum is great for gathering the pieces to the puzzle, but probably the ‘Worst’ place for intellectual discussions of candidate theories and evidence to take place.

So I guess we wait for the massive coverup to extrude the special interest message so far down the road, average folks don’t realize they been screwed again by the power brokers.

Edit: This is a multi-discipline system problem requiring experts from many broad backgrounds and expertise to get as close as possible to likely trigger initiating event and subsequent order of theoretical progressions.

 

[Optical98]

Thermo

No reason to stop the convo, please proceed. I'm not concerned about the 'mystery' posters, merely amused...
as I'm sure the other 5 posters on this thread are.

 

[FJBnomics]

Optical, thanks for even suggesting my input matters. What is needed is for IanCA to finish laying out his analysis , and IEGeezer. I have just been trying to follow their concepts and ask questions, out loud, to help understand their evaluations of available evidence. One problem on a forum like this is, we all bring tools to table but because it takes an understanding of multi-disciplines, we all grasp different concepts at a different pace. That is, say I ask a dumb electrical question, that is just raising the noise floor to the problem at hand, and causing a lot of back and forth for people to understand concepts outside their wheel house.

 

[zebraso]

Which scenario of Sym P.'s case 1,2, or 3, makes it more likely that the inner planter wall in zone A falls substantially below the level of the visible stampcrete along the tension crack line. Is there any case where you would expect to see the planter wall lying over on top of the visible stampcrete or wedged against it?

 

[FJBnomics]

Zebraso, I am thinking the diagonal movement in Zone 2, and break up of planter between 1 and 2 indicate movement or failure at or west of K-line first. Zone 3 and beyond where deck at south wall is draped, tells me the wall won there and pulled building columns South.

Also, with wall winning Zone 3 and east, would explain missing column early in garage video

 

[zebraso]

Are you saying there was rotational torque on the "missing" column?

Does that explain all rebar sheared of but one?

 

[FJBnomics]

Sorry typo above. Replaced deck with south wall winning. I think IEGeezer’s one way slab idea makes since. Perhaps some rotational torque on The missing M11.1 deck column from weak deck attachment,at South to North construction joint on East side, letting go to create one way slab with catenary tension tug of war between missing M11.1 column and L11.1 and South wall.

 

[zebraso]

Can anything about the amount of diagonal movement be inferred here:

Ok the idea I'm reaching for is that there could have been a large horizontal moment about a vertical center in the area of the step beam if the large area of the pool deck moves west even slightly. Obviously the columns that punched are more or less vertical but I don't think that means a significant horizontal moment did not exist.

 

[spsalso]

What I find interesting in the red-circled area is that there is so little damage to the column. The pavers tilted up as the deck fell down. You could almost just fold them back, and get back to normal.

Y'all might want to integrate that into your views of horizontal movements of the deck.

How is it that the deck dropped down that column like it was lubricated by KY Jelly?

I am sure NIST will reveal all, at some later time.



spsalso

 

[zebraso]

stampcrete held together better than the deck parking deck? KY? It's the basement parking so maybe. Too much KY. Must be the transients.

Edit: I find it improbable that the folded up stampcrete rolled or fell over the top bar and landed in that position. So I am rejecting any conclusions based on where it appears in these photos. IOW I think it was moved. I'm not drawing anything nefarious but I don't see any other way than someone did not like it where they found it. Maybe the hole there was a safety issue.

 

[IanCA]

6 Feb 22 22:18
Because the planter is continually supported by the wall and has no ability to impart significant bending moments to the slab.

Do you think it is possible that, over time, several of the vertical bars in the wall failed, the concrete failed, sheared, horizontally and zone A was, or portions of it were, resting on the top of the wall without being physically connected?

 

[IanCA]

I need a lot more help before I believe the corrosion driving the collapse theory. (Edit: along the south perimeter wall)

@Sym P. le, thanks for leaving the door open. I'll keep working on it, step by step, with backup.

 

[zebraso]

How is it that the deck dropped down that column like it was lubricated by KY Jelly?

I should have responded directly instead of editing my prior post. That was wrong, sorry.

You are correct. Nothing slid against that column. That's not the nature of the the punch shear the way these punched. That was pointed out. This was abnormal. I have to go back pretty far to find that explanation. But beyond that the stampcrete popped off because the adhesion was not all that great. And that did not scrape the column either because the rebar pushed it away. So that's why it seems inexplicable that it is found in a position as if it did scrape the column as if it slid down. So no KY is needed. It's easy to forget the reason these punched so easily.

 

[IanCA]

I did some reading up on pool chemicals, and how they control the pH and the chemical effects on concrete from the Portland Cement Association.

@thermopyle2.1
Sorry that it took me a while to get back to posting here.
Thanks very much for that helpful document. I believe the sections below are particularly relevant and I have added emphasis.

Chlorides dissolved in water can permeate through sound concrete or reach the steel through cracks. Chloride-containing admixtures can also cause corrosion. No other contaminant is documented as extensively in the literature as a cause of corrosion of metals in concrete than chloride ions. The mechanism by which chlorides promote corrosion is not entirely understood, but the most popular theory is that chloride ions penetrate the protective oxide film easier than do other ions, leaving the steel vulnerable to corrosion. The risk of corrosion increases as the chloride content of concrete increases

The important point for me about the cracks is that we know the waterproofing in the planters had failed, we know the parking deck did not have waterproofing, had cracks, had been repaired unsuccessfully in the past and we can see that the wall-deck connection in zone A had cracked horizontally. As a result, there was a path for liquid from the planters into the structure, into the concrete, and into contact with the steel.

ACI 318 chloride limit history

After much debate, a table showing maximum chloride ion contents for different types of concrete members first appeared 15 years ago in ACI 318-83,

When Champlain Towers South was built chloride ion content in concrete was uncontrolled. The cost of aggregate is closely related to haulage distance: aggregate cost. Aggregate from coastal regions has the potential for higher chloride ion levels. The area of the southern wall adjacent to the parking deck at CTS had two additional sources of chloride ions, including the exhaust from the pool equipment room.

The primary rate-controlling factors are the availability of oxygen, the electrical resistivity and relative humidity of the concrete, and the pH and temperature.

We know the garage area was designed with several fans to try and control humidity, that airflow meant the oxygen level was normal, the electrical resistivity would be relatively low, the irrigation runoff from the planters meant that the humidity of the concrete was high, but also variable, which is known to be worse than constantly high humidity, I will come back to pH in the future, and the ambient temperature is high. All bad conditions for increasing the rate of corrosion.