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Miami Beach, Champlain Towers South apartment building collapse, Part 19
17

Miami Beach, Champlain Towers South apartment building collapse, Part 19

Miami Beach, Champlain Towers South apartment building collapse, Part 19

(OP)

RE: Miami Beach, Champlain Towers South apartment building collapse, Part 19

I am not sure if this was considered in earlier posts, but there are alternative concrete types that can ensure a much longer life of the rebar in salt spray conditions. It is my understanding that the florida DOT is applying a 3" thick stucco of geopolymer cement on concrete bridges near salt water sources to provide long life for the rebar, as the permeability fo clhoride ions in geopolymer cement is more than 1000 times lower than with ordinary portland cement.

"...when logic, and proportion, have fallen, sloppy dead..." Grace Slick

RE: Miami Beach, Champlain Towers South apartment building collapse, Part 19

NIST says "FAILS Code By 50%! in pool area according to original ACI-77 and current ACI.
https://youtu.be/qgSitQ9iF_E

--Einstein gave the same test to students every year. When asked why he would do something like that, "Because the answers had changed."

RE: Miami Beach, Champlain Towers South apartment building collapse, Part 19

Additional news...

"More than two years after 98 people died in the collapse of a Florida condominium tower, federal investigators have released new details about the cause of the collapse. They're focusing on construction flaws on the building's pool deck.

Structural engineers with the National Institute of Standards and Technology say it's one of the most complex investigations ever undertaken. It began days after the 2021 collapse of the Champlain Towers South building in Surfside.

In a progress report, one of the team's leaders, Glenn Bell said the investigation continues to focus on the condo tower's pool deck. Investigators have previously said they found significant design and construction problems that left the deck weaker than required by building codes.

The team now has also found problems in how the concrete columns that supported the building were constructed. At a meeting at NIST headquarters in Maryland, Bell said, "These additional construction deviations further reduce the strength of the pool deck slab-to-column connections from the already compromised conditions that I reported in June.""

https://www.npr.org/2023/09/07/1198296548/surfside...

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

-Dik

RE: Miami Beach, Champlain Towers South apartment building collapse, Part 19

The National Construction Safety Team (NCST) Advisory Committee, Sept. 7, 2023 Public Meeting videos

Direct link to Sept. 7, 2023 video

24:40 - Discussion of additional slab reinforcement at columns

Quote:

At least 25% of all column strip reinforcement shall be centered over the column

Typically, that's four bars req'd over each column in each direction. Also, column strip reinforcement was spread over 20% to 40% greater area than called for on drawings.

33:20 - On average, concrete core tests reveal concrete to exceed compression strength requirements (though further analysis is still required as to broader findings and implications)

38:34 - Geotechnical studies - no evidence to date of voids/sinkholes beneath CTS. Potential for settlement is small, in order of 1/4". That magnitude would result in load redistributions from one column to the next of less than 5%.

RE: Miami Beach, Champlain Towers South apartment building collapse, Part 19

NIST can next investigate how the pool deck failure transferred to the adjacent building.

OR:

Why was the pool deck used to hold up the building? Because it did. While it was in place.

Yes, I know it's been discussed here, almost from the beginning. I just want to hear it from NIST.


spsalso

RE: Miami Beach, Champlain Towers South apartment building collapse, Part 19

spsalso - are the same/similar structural elements that caused the collapse of the south towers present in the still occupied north towers?

RE: Miami Beach, Champlain Towers South apartment building collapse, Part 19

I was interested in this part.

Quote (NPR)

At the meeting, Bell showed stills of a video recovered from a motion activated camera that has provided investigators with intriguing information in the final moments as the building collapsed.

Investigation head Judith Mitrani-Reiser says the team has recovered 24 computer hard drives that may hold videos and is actively working to rebuild seven of them. She said, "if even one of those seven has a short amount of footage, that would be a huge impact to our investigation."
https://www.npr.org/2023/09/07/1198296548/surfside...

RE: Miami Beach, Champlain Towers South apartment building collapse, Part 19

^^ definitely interesting. I’d imagine it’s likely that the drives are in a RAID configuration, unfortunately, which makes recovery without all of the drives and knowledge of the controller very difficult.

RE: Miami Beach, Champlain Towers South apartment building collapse, Part 19

"spsalso - are the same/similar structural elements that caused the collapse of the south towers present in the still occupied north towers?"


Don't know. If I lived there (Champlain Towers North), I'd be curious.

There's "caused". And there's "allowed". They seem to work hand-in-hand.

Here's a brief video:

https://www.youtube.com/watch?v=T5qp4NE4uzs

Looks like the answer to your question is "maybe/maybe not".



spsalso

RE: Miami Beach, Champlain Towers South apartment building collapse, Part 19

They were shoring up that building for awhile but haven’t heard anything since or what, if any, findings.

RE: Miami Beach, Champlain Towers South apartment building collapse, Part 19

Quote (spsalso (Electrical))

Why was the pool deck used to hold up the building? Because it did. While it was in place.

Is this some type of convoluted logic puzzle? Certainly if the deck could have been cleanly separated from the building in a timely manner the collapse would not have progressed to the tower. As stated in the question and answer period for the recent WJE webinar/report, Gary Klein answers that expansion joints in the pool deck would have most likely prevented the collapse of the main structure.

RE: Miami Beach, Champlain Towers South apartment building collapse, Part 19

I can see two interpretations of my statement:

"Because it did. While it was in place."

What I did NOT mean was that I approved or endorsed the idea of using the pool deck to hold up the building. Intentionally or unintentionally. I should have left those words out. Or perhaps put them in parentheses.

What I was getting at is that, so far, I'm hearing a lot about how the deck fell down. If ONLY the deck had fallen, this topic wouldn't have become 19 pages long. NIST still has to get to the second part of the collapse.

I first commented on the connection between the pool deck and the building on page 1 of this topic, on January 27, 2021.

How time flies when you're having fun!



spsalso

RE: Miami Beach, Champlain Towers South apartment building collapse, Part 19

tempis fuggit...

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

-Dik

RE: Miami Beach, Champlain Towers South apartment building collapse, Part 19

I just came across this but she had some more intrigue to the story.
A preliminary NIST report points to deviations from design in the Surfside, Florida, condo’s pool deck construction.

New details came to light Thursday regarding what caused the collapse of the Champlain Towers South building in Surfside, Florida, that killed 98 people in June 2021.

A report from the National Institute of Standards and Technology noted that the construction of the condominium’s pool deck deviated from design requirements and that the number of slab reinforcing bars centered over vertical columns was inadequate.

The NIST team also found that the reinforcing bars in the top of the slab in the vicinity of the columns were spaced farther apart than the design required. These deviations weakened the slab-column connections, the report said.

To me that sounds like a Surfside B&Z failure to properly inspect the rebar prior to allowing the pour to begin.

But then again this is Dade County which has the best inspectors money can buy.

Champlain Towers investigation yields more clues

RE: Miami Beach, Champlain Towers South apartment building collapse, Part 19

There was an important design change made in the months that the building was under construction. The change was sent to the EOR for approval. In effect the change removed a step-down of about 4"-6", as I recall. The architect or builder wanted to flatten this step down. When the design change was made, it essentially removed a beam which would have had 2 pieces of rebar, top and bottom. That area was revised into what became more of a "slab" than the beam it had been. This was in the exact area in the parking garage where sagging and water leaking had been observed (and patched and painted) for decades. There is no doubt in my mind that the deterioration in that slab was the location of the initiation of failure for this building. All other construction errors, like rebar spaced further than the design specified or fewer bars than shown on design drawings, might contribute 0.5% to the collapse; the removal of a beam such that a slab transfers load that it is not designed to support -- not by a long shot -- has to be at least 99.5% of the cause of collapse. This design change was probably sent to a junior engineer to review and approve. Not having designed the structure, the engineer may not have recognized the significance of the change. [I admit that the "junior engineer" idea is speculation. Paper records other than the designs on file with the county have undoubtably been trashed by now, and all people involved are likely dead (over age 75 or so), so we will never know what transpired in the design change process.]

Other factors discussed above and in other threads:

(1) Sea spray or salt did not materially contribute to the collapse. Corrosion may have allowed the building to collapse a few days, months, or years earlier than it would have if it were built 100 miles from the ocean, but the rebar and concrete would have eventually deteriorated due to rainwater just the same.

(2) Isolating the pool deck from the building structural support system would have prevented the pool deck failure progressing to a building failure. This is the difference between minor injuries and, at most, 1-5 deaths vs 98 deaths.

(3) Inadequate shear walls in building -- this is related to the severity of the collapse, and is secondary to the cause of collapse

Sorry that I don't have time to go back and find the screenshots of the original and revised design. As I recall, this was discussed earlier in one of these threads, although it may have been on another forum.

RE: Miami Beach, Champlain Towers South apartment building collapse, Part 19

Quote (NOLAscience (Structural))

In effect the change removed a step-down of about 4"-6", as I recall.

The step beam and beam type A deleted from plans stamped 1981 vs original (1980). This was noted a long time back in this topic. Are these beams present on the North Champlain Tower? Maybe this was mentioned somewhere in the past 18 pages. If so it's one less reason to be overly concerned about the other site. I think they are taking measures to improve the punching shear.

RE: Miami Beach, Champlain Towers South apartment building collapse, Part 19

Comparison of original design versus revised build copy with removed steps and BMA's highlighted.





Undoubtedly, the removed features would have reinforced the broad area of weak slab and offered some interruption between the pool deck and lobby parking. Is it wishing to much for NCST to study this aspect of the failure, that is how well are significant revisions evaluated prior to approval?

Note: The pool deck slab was raised one foot with implications towards garage clearance, building height, or excavation requirements.

RE: Miami Beach, Champlain Towers South apartment building collapse, Part 19

I believe this structure was "self-inspected".

Apparently, the building department thought it was over their head. I expect properly. I don't understand why the building department did not then hire an outside expert, rather than allow self-inspection.

I do wonder to what extent the city building inspector DID show up. It's not like they could keep him out. But, for whatever reason, he missed them errors.

The EOR has his name on it. If he had a junior apprentice woodchuck do the work, he clearly had every confidence in that 'chuck: his name is on it.


spsalso

RE: Miami Beach, Champlain Towers South apartment building collapse, Part 19

Jeff Ostroff has a new Youtube video on the building:

https://www.youtube.com/watch?v=jBzDtdZlXx0

He describes in the early parts that NIST discovered a severe lack of rebar crossing the columns in the pool deck area. He mentioned that the structural engineer would surely have been upset if he had known. As an illustration, he showed someone banging his (hard had protected) head on a wall.

Uh. The structural engineer SHOULD have known. He was also the inspector. He signed off on the rebar placement.

I am surprised Jeff didn't comment on that.

[Note: the "severe lack" mentioned above doesn't mean there was NO rebar there. There was half as much as called for in the plans.]

spsalso

RE: Miami Beach, Champlain Towers South apartment building collapse, Part 19

We always put reinforcing over the column area when I was with RJC. I don't recall the percentages anymore for slabs with drop panels (over 40 years back) I think it was 80% and 20% for drops with 80% going in the column strip and 20% over the column. For slabs without drops, there were two other ratios based on the size of the column... a greater percentage for 12" wide columns and a lesser percent for 24" wide columns, adjusted for columns in between...

This was based on work that Per Christoffersen had done with a loaded plastic model and a dial guage to determine curvatures. The model used to be in the Toronto RJC office. RJC used to use these for designing office building slabs.

Forgot to add, I always put a couple of 25M (#8) in the bottom of the slab for narrow columns, to preclude punching shear.

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

-Dik

RE: Miami Beach, Champlain Towers South apartment building collapse, Part 19

Quote (spsalso (Electrical))

The structural engineer SHOULD have known. He was also the inspector. He signed off on the rebar placement.

Yeah. So what is the thinking here? It does not seem plausible that it was an error or "mistake". Were there last minute calculations based on some revised load estimates? Seat of the pants to save a few bucks? Anything? I know it's wrong but why was it done this way? I can't believe they missed a note in the drawing. How else would they guess the percentage centered on column in the strip?

RE: Miami Beach, Champlain Towers South apartment building collapse, Part 19

"So what is the thinking here?"

My thinking here is that:

The structural engineer never showed up to do the rebar inspection. And that the pour happened anyway.

OR

The structural engineer showed up to do the inspection but did a thoroughly inadequate job.

OR

The structural engineer showed up for the inspection, saw the improperly placed rebar, and did not act on that knowledge.



spsalso

RE: Miami Beach, Champlain Towers South apartment building collapse, Part 19

I tend to believe it's a casual indifference. None of these actors are yesterdays child.

There is nothing like a true inspection report. "The plans call for a 4" stitch weld every three feet. The welds are only 3.5"." Not many words need to be exchanged as the welder spends another day on the cherry picker.

RE: Miami Beach, Champlain Towers South apartment building collapse, Part 19

From Canadian code:

-FOR INTERMITTENT WELDS, LENGTH SHALL NOT BE LESS THAN THE GREATER OF 4 TIMES THE WELD SIZE OR 40MM (1-1/2”). FOR COMPRESSION MEMBERS, THE MAX CLEAR SPACING BETWEEN WELDS SHALL NOT EXCEED 12”. FOR TENSION MEMBERS, THE MAX CLEAR SPACING BETWEEN WELDS SHALL NOT EXCEED 18” (CSA W59 11.4.13.2).

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

-Dik

RE: Miami Beach, Champlain Towers South apartment building collapse, Part 19

Sorry dik, that wasn't an exact quote. The incident was real and the solution could not have been easier and it was a long time ago. The point being that if the inspector takes his responsibilities seriously, managing work quality gets easier. Once word gets out that performance is expected, everyone remembers what they're supposed to do.

Thanks for bringing out the code though.

RE: Miami Beach, Champlain Towers South apartment building collapse, Part 19

US code is likely similar... not even close to code compliance. I occasionally review construction, but that would have 'jumped out'. It distresses me that there was no one charged with criminal negligence for all the deaths. I guess it's the way they do things in Florida. The system is broken.

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

-Dik

RE: Miami Beach, Champlain Towers South apartment building collapse, Part 19

"It distresses me that there was no one charged with criminal negligence for all the deaths."

Who is still alive who might be charged?

Notably missing, however, is any interest by any governmental authority to examine and make public whether there WAS such negligence.


spsalso


RE: Miami Beach, Champlain Towers South apartment building collapse, Part 19

or businesses associated with it? or those neglecting the upkeep? or the EOR that did the sloppy 'repair'?

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

-Dik

RE: Miami Beach, Champlain Towers South apartment building collapse, Part 19

I happened to be in Miami this past week. We walked on the beach path and swam in the Atlantic. This is the Champlain Towers site, 28 Jan 2024.

RE: Miami Beach, Champlain Towers South apartment building collapse, Part 19

Did we ever have the plans for the parking levels and the first floors of the Champlain Towers NORTH? Does it have the "step" that was eliminated in CT South?

RE: Miami Beach, Champlain Towers South apartment building collapse, Part 19

You should have walked by the Champlain Towers North building also, they changed their name, they are no longer called Champlain Towers.

RE: Miami Beach, Champlain Towers South apartment building collapse, Part 19

Quote (NOLAScience)

Did we ever have the plans for the parking levels and the first floors of the Champlain Towers NORTH? Does it have the "step" that was eliminated in CT South?

I do find it strange how there hasn't been any follow up or media information on CTN after they were reportedly shoring up some spots. Nothing about the design, how similar, etc. Probably on purpose to protect property values, just like renaming mentioned above lol. But as someone very interested in the causes and such, I'd love to know these things.

RE: Miami Beach, Champlain Towers South apartment building collapse, Part 19

They will reinforce their property values by reinforcing the structure with appropriate oversight.

RE: Miami Beach, Champlain Towers South apartment building collapse, Part 19

STCbus, I live locally here to CTS, I can drive there in 40 minutes. The local news stations did cover the added pole shores in early 2022 when they were first added, and I have already done a video on these added poles at CTN analyzing why they were put in the spots that they chose, and I mentioned it also on my 1-year remembrance video, where I was on site there for the ceremony, and Jill bidden was there along with Ron DeSantis.

Also The local news here 2 years ago mentioned the Champlain Towers East building also added pole shores in their garage and they showed some severely crumbling columns in their garage too.

RE: Miami Beach, Champlain Towers South apartment building collapse, Part 19

^ yeah I remember that just was curious because I don’t think the results were ever reported, like what was done permanently and blueprints if it has the same design flaws like mentioned above.

RE: Miami Beach, Champlain Towers South apartment building collapse, Part 19

See page 217 of 336 in 8777-collins-ave-1979-plans.pdf for the CTN lobby level framing plan. It does not have the double-H of BMAs spanning KLM 9.1-11.1 that I believe doomed the CTS tower from the pool deck collapse. (Note the garage ramp in CTN is the K-L bay, not the L-M bay as in CTS; as the entire east wing is shortened by 2 or 3 structural bays, relative to CTS.) I don't know if that page is the newest one in the public PDF, or how it relates to as-built.

RE: Miami Beach, Champlain Towers South apartment building collapse, Part 19

I didn't get caught up, here, but has there been any prior discussion of potential backstay effect when it comes to the pool/parking slab?

Backstay Effect, Tocci, Levi, June 2012, Structure Magazine

As a side note, was the backstay effect in common engineering parlance as a phenomenon back in, say, 1978?

RE: Miami Beach, Champlain Towers South apartment building collapse, Part 19

Quote (spsalso (Electrical))

So what is the thinking here?"

My thinking here is that:

The structural engineer never showed up to do the rebar inspection. And that the pour happened anyway.
OR
The structural engineer showed up to do the inspection but did a thoroughly inadequate job.
OR
The structural engineer showed up for the inspection, saw the improperly placed rebar, and did not act on that knowledge.
I believe there is at least one more possibility. The structural engineer could've known what was happening but was paid to ignore it!

RE: Miami Beach, Champlain Towers South apartment building collapse, Part 19

Quote (expatrie (Structural)21 Feb 24 21:03)

... has there been any prior discussion of potential backstay effect when it comes to the pool/parking slab?

After nineteen pages, I don't recall. It's an interesting topic.

The article seems to focus on grade level and lower diaphragm interactions with the tower system. In the Champlain Towers situation, the evidence is leaning towards design/construction shortcomings of the grade level slab coupled with abuse of same with overloading pool deck renovations triggering its collapse.

I don't recall hearing any investigative avenues regarding the possibility of wind effects pushing the tower against the diaphragm, which would be an inverse cause/effect of backstay.

RE: Miami Beach, Champlain Towers South apartment building collapse, Part 19

I didn't mean it was causing anything I meant was backstay discussed at any point in here. It doesn't seem like backstay was around as a concept during the original design timeframe. I haven't found any literature that far back. All I found was a 2010 document involving seismic design. I guess Adebar mentions it in 2008, but I don't see any references back in his citations.

Design of High-Rise Core-Wall Buildings: A Canadian Perspective, Adebar, 14th World Conference on Earthquake Engineering, October 2008.

Alright, now I do. Never mind I think I got it traced back to at least 1983.

Force Distribution Between the Core and Subgrade Structure of High Rise Buildings Subjected to Lateral Load Induced Forces - Bevan-Pitchard, Man, Anderson, Proceedings of 4th Canadian Conference on Earthquake Engineering, 1983.

Bevan-Pritchard doesn't cite any other published research....

RE: Miami Beach, Champlain Towers South apartment building collapse, Part 19

Quote (lexpatrie (Structural) 22 Feb 24 19:25 I didn't mean it was causing anything I meant was backstay discussed at any point in here.)


I have followed this thread from the beginning and I don't remember backstay being mentioned at all. Since backstay would apply to buildings subjected to large lateral forces, and with no theory for how a lateral force was applied to this building but no other buildings in the area, it would seem that there may be other threads on this forum that would be better suited to the discussion of backstay design considerations.


RE: Miami Beach, Champlain Towers South apartment building collapse, Part 19

Quote (Mark R (Mechanical))

The structural engineer could've known what was happening but was paid to ignore it!

So instead of negligence then, we would be broaching the subject of criminal malfeasance. Very interesting. It would seem only reasonable and responsible to consider this possibility.

RE: Miami Beach, Champlain Towers South apartment building collapse, Part 19

The agenda for the next NIST NCST meeting is out, they will be talking on March 7:

https://www.nist.gov/system/files/documents/2024/0...

They got a busy agenda, starts at 9 am and runs until 5 pm, much more than the September update, and looks like they got a ton more of speakers lined up, and most of the individual project managers from within the investigation. This should be a very meaty discussion.

RE: Miami Beach, Champlain Towers South apartment building collapse, Part 19

Maude, here is the latest timeline time stamps showing the initiation of the east tower collapse at 1:22:17 AM, and the time stamps of the related security cameras, including the new security camera video they acquired in December, from the 87 Park condo next door, looking down the beach access boardwalk along the south side of the pool.

They also show the time stamps of the security camera from inside the corridor.

Do you need to adjust any time stamps on the spreadsheet based in any of these latest times?

RE: Miami Beach, Champlain Towers South apartment building collapse, Part 19

Vimeo of NIST meeting - https://vimeo.com/event/4119207

Included is some more video analysis including a color image of RING camera unit from the day before collapse.

RE: Miami Beach, Champlain Towers South apartment building collapse, Part 19

I am waiting for my video to upload to youtube, where I summarized the meeting among other things, and reviewed the new security camera videos they found.

RE: Miami Beach, Champlain Towers South apartment building collapse, Part 19

Can you post a link?

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

-Dik

RE: Miami Beach, Champlain Towers South apartment building collapse, Part 19

People here don't like it when I post links to my videos. Just look me up on YouTube, my video finished uploading just now!

RE: Miami Beach, Champlain Towers South apartment building collapse, Part 19

Jeff Ostroff? or does it have a title?

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

-Dik

RE: Miami Beach, Champlain Towers South apartment building collapse, Part 19

It is called "Miami Condo Collapse NEW Security Camera Video, Analysis Updates"

unless I need to change it later for SEO purposes, but that is the title of it for now

RE: Miami Beach, Champlain Towers South apartment building collapse, Part 19

Thanks... will take a gander.

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

-Dik

RE: Miami Beach, Champlain Towers South apartment building collapse, Part 19

It's a pretty good write up... a couple of minor issues, but generally OK.

I have a couple of real issues with this:
  • The condo owners should be compensated for their loss and there does not seem to be anything in place.
  • The EOR made several serious errors. For this reason, their liability insurance should provide compensation.
  • There is no responsibility of the condominium board, and they should be charged with negligent homicide. Failure was a result of their inaction.

If this doesn't happen, it will occur in future.

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

-Dik

RE: Miami Beach, Champlain Towers South apartment building collapse, Part 19

@Jeff Ostroff.

Thanks for calling out the timeline detail. I have been so busy renovating my 1903 house (which will definitely collapse in a major earthquake, because it’s full masonry) that I have been paying no attention to this topic.

I checked the timeline spreadsheet, and it looks like I can add the seconds to it to make it match the NIST timeline.

I have to say that I am proud to have been able to provide to this forum for nearly two years what has proven to be an accurate and thorough witness timeline, despite having had to rely on media quotations instead of on personal interviews.

RE: Miami Beach, Champlain Towers South apartment building collapse, Part 19

Quote (dik)

There is no responsibility of the condominium board, and they should be charged with negligent homicide. Failure was a result of their inaction.

That won’t hold up. The Board was constantly thwarted by the condo owners themselves, who refused to support proposals to make necessary structural repairs. They only wanted to pay for a pretty lobby update. One of the previous Board presidents resigned, moved out, and sold her unit in disgust. The condo owners were in many cases elderly and unable to afford assessments, and in other cases LLCs who acquired their units as investments and planned to take their profits and then sell without paying major assessments.

The sad and terrible reality is that the condo unit owners in essence brought about their own doom by failing to agree to assessments over the years.

RE: Miami Beach, Champlain Towers South apartment building collapse, Part 19

It would have been in the authority of the board to have started condemnation proceedings to get the building evacuated for structural problems long before the collapse. This would have driven the LLCs to act to protect their investment.

RE: Miami Beach, Champlain Towers South apartment building collapse, Part 19

Quote (The sad and terrible reality is that the condo unit owners in essence brought about their own doom by failing to agree to assessments over the years.)


Thanks...

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

-Dik

RE: Miami Beach, Champlain Towers South apartment building collapse, Part 19

I’ve been going through the presentations and recordings.

In relation to the Witness Statement Timeline, note that the crash at 1:10 AM is not called out in the NIST timeline, even though they are being very careful to keep their options open regarding the possible location (tower or deck) of the initiating event. We know from the media that this crash was heard by Shamoka Furman in the lobby and by the Nirs in 111. It is what triggered Sara Nir to go to the lobby, where she and Shamoka were when the pool and car deck collapsed at 1:15. I am leaving the 1:10 crash on the spreadsheet.

From a witness statement perspective, among the most helpful images were those of the engineer Paolo Longobardi, who apparently drew his perceptions of deck collapse origin and progression as viewed from Unit 309. We had already captured his verbal description on the spreadsheet, which for some reason NIST claims was not reported in the media.

New to me was the description of horizontal cracks in the building facade and the first floor glass exploding. I can’t tell whose observation this was, although the likely witness is Paolo Longobardi, or exactly when this observation was made (after the deck collapse? It’s confusing because the Longobardis were evacuating via the east staircase.) I will try to figure out how to add this to the spreadsheet.

Here is the current NIST failure sequence slide, which relies strongly on the synchronization of all the videos they currently have on hand.

In the discussion recordings, there is a discussion of the banging sounds heard prior to 1 AM. Dr. Ganapati refers to “he” as the source. This makes it sound like the Nirs are relying on Gabe to be the family spokesperson, rather than allowing Sara and Chani to contribute individually. If this is true, it explains why they don’t pick up on Chani’s statement that she heard banging sounds as soon as she got home from babysitting at around 11 PM. It doesn’t explain why they don’t call out the 1:10 AM crash that sent Sara to the lobby, as they all heard it. If it’s revisionism, it may be an example of why eyewitness testimony is so unreliable. I was dismissed from a voir dire once for stating that under oath. We may learn more six months from now.

RE: Miami Beach, Champlain Towers South apartment building collapse, Part 19

NIST is wierd. Next they'll tell us they found out the sky is blue.

RE: Miami Beach, Champlain Towers South apartment building collapse, Part 19

The Original Eighty Seven Park CCTV Collapse Video

I did search here and elsewhere far and wide for answers first before posting. These (largely) excellent educated threads were my #1 goto after the collapse amidst all the other internet noise. Thanks to all for that.

[Qualifier: This is strictly level-headed fact seeking, non-accusatory, and no conspiracies implied.]

The famous publicly released collapse video was a poor cellphone capture of a monitor during playback of the Eighty Seven Park (ESP) CCTV recording, presumably in their security office.

. Who made the cellphone video? My top guess is an ESP employee who felt it needed to get out, but wanted to stay anonymous to avoid repercussions.

. Sports reporter Andy Slater was first to publicly post it. Who sent the file to him, and was it the same person who recorded it?

. AFAIK neither ESP or authorities have acknowledged the existence of or discussed the original higher-quality CCTV video. Why not? I've not even seen public questions or discussion about it, weirdly enough.

. The original is also likely to have crucial footage before and after what the cell video captured.

Why such a lack of public information or discussion around something of such potentially major evidentiary and investigative importance? Seems it would be important to the public and affected families as well.

RE: Miami Beach, Champlain Towers South apartment building collapse, Part 19

I understand your personal curiosity, but why does it matter to the survivors or the aggrieved families who recorded the video? Andy Slater is under no obligation to reveal his source, if he even has an identity, so you can’t get it out of him.

It would be great, as you said, to have plenty of frames before the collapse begins. If a high res version existed, though, NIST would probably have it. NIST has proceeded to analyze the copy, so whatever happened to the original it is not stopping them.

The original may have been lost due to an error, automatically written over, or deliberately destroyed to protect someone. I suspect, based on no fact, that it’s the first or second possibility. FWIW, the owner of the building did pay out part of the settlement, while admitting no fault.

So I think this is a moot point all these years later. At every meeting, NIST provides a status report on the hard drives they have been trying to read, and requests citizens to provide videos, photos, and other evidence that might help their investigation. Every meeting, Pablo Langesfeld, whose daughter Nicky died in the collapse, rises to object to how long the investigation is taking, but never expresses concerns about the quality of this video or who shot the cell phone version of it. I monitor a survivor group, and no one is worried about the video in there either.

RE: Miami Beach, Champlain Towers South apartment building collapse, Part 19

Great food for thought, thank you. Here are some clarifications.

ID of Slater's source: Not important; only an interesting part of the complete story.

Importance of original video to families: Strictly if it were me, I would want know it exists and view it. Obviously everyone's different.

Importance to public: I do think the original should be released and part of historic public record. If NIST indeed has it, they may have very good reasons they've never said so. We all have educated guesses and conjecture, but I'm interested in their official reasons. If it was lost, the why and how are also important facts.

I believe all consequential unreleased facts and evidence from this catastrophic event should be on public record. Perhaps it'll all come out in the final report.

RE: Miami Beach, Champlain Towers South apartment building collapse, Part 19

2
(OP)
The NIST media manager acknowledged to me that NIST has the original, but not the rights and so cannot release the cleaned-up version.

SF Charlie
Eng-Tips.com Forum Policies

RE: Miami Beach, Champlain Towers South apartment building collapse, Part 19

Offhand, I know this isn't on topic, but does anybody out there have the 79 pages of structural calculations from Harbour Cay?

Investigation of Construction Failure of Harbour Cay Condominium in Cocoa Beach, Florida, NBS 145, Lew, Carino, Fattal, Batts, Aug 1982 mentions them.

To quote:


I'm asking as this seems like perhaps somebody who's following this thread might also remember that building.

Any other places one might inquire as to those calculations would be appreciated (All the sources I have tried who wrote articles on it, based it off the NBS report and didn't have the actual calculations, i.e. Delotte).

Also, sorry, on a more related note, I thought somewhere in this discussion somebody separated the drawings by discipline (Structural/Mechanical/Architectural, etc.). I am working back through the thread trying to find that post, but haven't found it yet, so if anybody knows where specifically that post is, it'd be appreciated. I've gone through Part 1 - 6 already.

RE: Miami Beach, Champlain Towers South apartment building collapse, Part 19

If this helps, on my Linux box, the pdf reader allows saving individual or a selection of pages into a new document.

RE: Miami Beach, Champlain Towers South apartment building collapse, Part 19

Good for pointing that out. Being able to save pages or selections is an option that is controlled by settings in the original document. In this case the pdf is from scanned images** and a piss poor job of scanning at that.


**To get better scans (recognizing the document here was scanned by someone else) put a black sheet behind the page. This prevents the retroreflection from the following sheet that not only creates print-through of the following sheet, but also the reverse of the page being scanned. The scanner can handle the white balance from the front reflection of the page being scanned.

RE: Miami Beach, Champlain Towers South apartment building collapse, Part 19

[quote MaudST][The sad and terrible reality is that the condo unit owners in essence brought about their own doom by failing to agree to assessments over the years.]

This whole notion that the condominium board failed to take action is inaccurate. If you pay attention to the presentation by Gary Klein, the association had performed a condition assessment, earlier than the required deadline, and was in the process of receiving repair drawings and specifications to address what was found during the assessment. However, the repair drawings and specifications did not have any repairs that would have addressed the punching shear original design flaw in the pool deck. This is because the consultants performing the assessment did not identify a design deficiency in that area. The majority of the issues and repairs identified in the 2020 assessment had nothing to do with structural issues. If you look at that scope of work, it's strongly geared towards stucco, windows and doors, balconies and some waterproofing.

For the majority of the life of the structure, The punching sheer distress would have not been visible since it would have been concealed and located on the top surface of the pool deck. Only late in the failure progression, likely occurring in the last few months of the structure's existence would the punching sheer have been manifested in a way that would be visibly evident from the underside. Unfortunately for the consultants hired by CTS, they happened to make a return visit during the period of time when evidence of the punching shear failure was beginning to manifest in a visible way (after their initial assessment). Those consultants failed to identify the significance of what they were looking at, contributing it to issues with the planter on the surface of the deck. At no point, was the Association ever aware of a punching shear issue in the pool deck or that urgent action was warranted. Further, had they successfully completed the scope of repair work identified in the assessment and other corresponding repair drawings, they would have a lot of new windows, new stucco, and some new waterproofing, but the structure likely still would have failed.

While there are some small deviations in the original construction (wider bar placement above columns/variable cover) they have not been found to be substantial, with the construction at the critical columns being in general accordance with the original design drawings. Accordingly, while the placement could be a little bit better, and inspector wouldn't have identified an issue if it was pretty close to what it was designed as. When NIST has said, the bar placements are slightly different than what was specified, they don't mean widely different. Looking at the original design, even if they built it per the engineering documents, it likely would have still failed. Perhaps even sooner since, two deviations in the construction include, the actual concrete had a higher compressive strength then what was specified, and the reinforcing at the columns was placed closer towards the top surface than the bottom. Both of those deviations actually increase punching shear resistance, and the Gary Klein presentation identifies some of this, as he is accounting for increased capacity based on these values. Also, the Gary Klein investigation and the NIST investigation have not found substantial corrosion or deterioration in the areas associated with the failure initiation.

The deck failure progressing to the structure is an unfortunate or unlucky design detail. There's nothing inherently wrong with that design detail, it's just that with this collapse mechanism it allowed the collapse to continue to the structure. There are a tremendous amount of other design details that are just fine unless a portion of the structure collapses, we are not critical of those since we don't want portions of any structures to collapse.

The false narrative of gross neglect and deterioration bringing about the failure of the structure should be addressed more widely.

The big picture issue is, a punching sheer failure in the pool deck due to an original design error initiated the collapse. That design error wasn't limited to a single column; rather, multiple columns throughout the pool deck did not have the minimally required punching shear capacity at the time of the original design. This is likely why the failure of a single column went progressive, with adjacent columns also punching.

The pool deck failure was exacerbated by decisions to add dead load to the deck in the '90s. There was an engineer and contractor involved in that work, and that engineer also failed to perform a design check for punching shear at these columns despite adding substantial dead load.


It was a design failure by the original engineer, along with a myriad of other unfortunate circumstances, which is why this collapse is so rare, so shocking, and so significant.

RE: Miami Beach, Champlain Towers South apartment building collapse, Part 19

If I had to point fingers, I would aim at the '90s era deck work. I wonder how it passed muster that a significant load could be piled onto the deck without raising concerns of permitting authorities.

RE: Miami Beach, Champlain Towers South apartment building collapse, Part 19

Quote (Dave.Smith.NYC (Structural))

The false narrative of gross neglect and deterioration bringing about the failure of the structure should be addressed more widely.

You make a strong case. The underlying current in the victim blaming seems to be that if they had only done more assessments and done them earlier over time that fatal flaws would have been detected. You are making the strong case (I think) that this is simply not true. It may be the most important point. Some punch calculations were made, all found to be exceeded and still nothing further was done to review the entire structure for punch shear to include the pool deck. So I don't know how any amount of further, earlier assessments could have addressed it. What is the scenario given what we understand about existing engineering reviews that would have brought the desired result?

RE: Miami Beach, Champlain Towers South apartment building collapse, Part 19

A powerful argument and an excellent discussion. While the Board may have been misinformed by consultant failures, the situation is not cut and dried. The Board had difficulty getting assessments approved, especially in the more recent years, which is why the estimated cost of repairs skyrocketed between the penultimate estimate and the last one. At the time the building collapsed, some unit owners were still canvassing the building in an attempt to stop the renovations. It is this later period of time that I was pointing to, during which one frustrated Board Chair resigned in frustration, moved out, and sold her unit.

I apologize for making a statement that implies that only the victims were to blame for the failure, when of course there were structural and design reasons for the failure. However, there were also many years of squabbling, foot dragging, and outright resistance that delayed repairs that may have gotten that deck unloaded in time to prevent the progression that brought down the building. Delay caused by unit owner resistance can be considered a contributing factor, but not a root cause.

RE: Miami Beach, Champlain Towers South apartment building collapse, Part 19

I thought the extra beam that was taken out when a step down was reduced was a major issue as well?

RE: Miami Beach, Champlain Towers South apartment building collapse, Part 19

Quote (Dave.Smith.NYC)

This whole notion that the condominium board failed to take action is inaccurate. If you pay attention to the presentation by Gary Klein, the association had performed a condition assessment, earlier than the required deadline, and was in the process of receiving repair drawings and specifications to address what was found during the assessment. …

You're not wrong, but I feel that there's more to it.

The 40 year deadline shouldn't have been used as an excuse to neglect the structure in the past. It shouldn't ever be a case of do the bare minimum for 39 years, then patch it all up in the final year before the deadline. That falls on both the board and local government. The water damage and intrusion into the garage and various instances of cracking and spalling over the years were clues that all was not well with the pool slab.

The other part where it is fair to shine a spotlight on the board/association is the chronic lack of funding of reserves over the lifetime of the building, and general reluctance to spend money on repairs. If they had fully funded reserves over the years, the chances of finding themselves facing a $9-15M crisis would have been greatly reduced. Additionally, earlier repair attempts might have been to a higher standard and/or involved a more comprehensive structural assessment if the board/association had not been so reluctant to spend money on the structure over the years. I see a pattern of kicking the can down the road, trying to spend the bare minimum on structural maintenance.

Yes, the MC report did not sufficiently predict/explain the risk, and the engineer that inspected the fractured and dropped planter missed a critical sign of immediate structural peril. There's also the person from the town's buildings department who said something like "the building is in good shape" (but there are different way to interpret that, such as the work for the 40 year recertification being in good shape). Those things are not on the board/association.

RE: Miami Beach, Champlain Towers South apartment building collapse, Part 19

Quote (zebraso)

What is the scenario given what we understand about existing engineering reviews that would have brought the desired result?
Well for the engineer in the '90s that added additional deadload; that action would have required them to analyze enough of the existing structure down to grade to satisfy that the existing structure could satisfactorily carry the additional loads. If that analysis was performed correctly, it would have included the punching shear check at the deck to column connections. That check would have identified a gross under design (especially relative to prescriptive code requirements) and likely would have triggered temporary shoring and strengthening to increase the punching shear capacity at the columns.

For the Morabito work from 2018 to 2021, they likely would not have seen the evidence of a punching sheer issue the majority of the time they were there. The loan exception is the planter deflections that would have manifested only in the last month or two prior to the collapse. They did not recognize this as evidence of punching share but apparently attributed to issues with the planter itself.

I saw the notes from Gary Klein that Morabito had in their file structural analysis software data printouts that indicated punching shear deficiencies with the original design. I have not seen any information regarding why Morabito didn't take action regarding these data printouts. It's possible, but they were not using the software with that purpose, and simply did not look at all of the data printouts, I have no idea anything I would say would be conjecture.

What we know is that all of the photographs and language in Morabito's inspection reports our focused on maintenance level near surface corrosion, and associated corrosion-related cracking. The repair drawings address this kind of distress as well, though largely not in the critical areas of the pool deck (work done near ramps, balconies, etc.). Again, had CTS actually performed all the work in the repair drawings, there would not have been any strengthening that would have improved the column-to-deck connections (in the critical areas of the pool deck). Of course, hopefully during the process of that work, something would have been identified by the engineer to make them aware of the design problem at the deck to column connections (in the critical areas of the pool deck).

Ideally, The engineer would have identified the visual evidence of the punching shear problem when they saw it manifest with the planter deflection. Prior to that, the only way they would have likely identified it would have been from a original design review which is not something typically done, or is not something typically necessary to do during a condition assessment (without evidence suggesting it be done). Design reviews are typically only done when asked, or when changing the load (like they did in the '90s).

Despite everything I just said, I've not seen evidence that suggests Morabito did it particularly terrible job or anything like that. I wish (and I'm sure they wish) that they would have recognized the punching shear problem either through their calculations or from the planter deflections. They didn't, they missed it, and they missed an opportunity to help avoid a terrible tragedy. Any competent engineer, that would have recognized the significance of the issue associated with the punching shear design would have been raising all kinds of seriously substantial alarm bells, down to notifying the building official out of ethical responsibility if the ownership was not going to shore those column connections as soon as possible.

CTS was spending money on their building (the had just started a roofing project), if they knew that their pool deck was going to collapse, they would have shored it and repaired it.

Still, I don't think that even if an engineer recognized the pending punching shear problem, that anyone would have suspected the entire building would have been at risk. Most engineers likely would have just said shore the pool deck or do not use the areas above or below it until shoring is in place. I'm not sure people would have suspected the progression that occurred to have occurred, again all of this is why this is such a rare and shocking tragedy.

RE: Miami Beach, Champlain Towers South apartment building collapse, Part 19

Dave - I don't think this is accurate. Please consider revising your post, if possible.

In fact, I think these comments show that you haven't looked at the repair drawings by Morabito. You should review the Morabito drawings before you comment on what was or was not in them.

There were details showing reinforcement in the column area, by Morabito, As disclosed on the Surfside web site: Champlain Towers South, Phase IIc drawings


Source: Morabito Phase IIc, Champlain Towers South drawings, 4/27/2021 Not for Construction

These look a lot like approaches to fix a punching shear problem. Are they in the right locations? That I don't know. The nature of the detail suggests repairs involving the pool deck because there's no column depicted above it in the detail.

Now, it's possible that these drawings were issued after the collapse, I don't know about that. But there was definitely a report that Morabito issued after the collapse.

As to Mr. Klein, this seems inaccurate as well, unless Phase IIc drawings were only issued after the collapse. What's your source, please, because many of us would be interested in seeing that document, and I don't think it's in the 19 threads here.

I've seen a lot of people here post about an obvious punching shear problem, but I've not seen any load calculations or strength calculations, as I recall. I haven't read the entire sequence of 19 thoroughly, though. I do recall a YouTube video where somebody did calculations, though I don't recall seeing the actual calculations just a few screen shots of their work and discussion of how they arrived at it.

As to the plausibility of Morabito being totally unaware of s punching shear issue, Frank Morabito wrote an article where he discussed the Dauphin towers fix that was done by Morabito and that report specifically mentioned punching shear. That to me suggests that they checked it and intended to address it via structural strengthening at the slab/column.


Source: Dolphin Towers Condominium Remediation, Morabito, Structure Magazine, July 2016

Regarding the "engineer" in the 1990s, was there actually an engineer there? Or was it a contractor adding a bunch of weight without an engineer? I haven't seen any documents on that subject.

RE: Miami Beach, Champlain Towers South apartment building collapse, Part 19

Quote (lexpatrie)

Please consider revising your post, if possible.
Thank you for your comments and conjecture. I did revise the post to be more specific at a few locations by including the clarifying language "in the critical areas of the pool deck)".

Quote (lexpatrie)

Are they in the right locations? That I don't know.
Lucky for us, the same Morabito drawings you linked, and that I had previously reviewed do in fact tell us where they designed these drop panels. Unfortunately, as I mentioned, they are nowhere near the critical areas of the pool deck. I annotated the plan in red to show the locations of the drop panels, the area circled in blue are the critical columns that initiated the collapse, and the areas in green are the other pool deck columns that were underdesigned in terms of punching shear.


Quote (lexpatrie)

As to Mr. Klein, this seems inaccurate as well...
I'm not sure exactly what you're referring to here, but near the 14-minute mark of this presentation by Dr. Matt Fadden who appears to work for (or with) Mr. Klein, they discussed the punching sheer printouts from Morabito.
https://www.wje.com/knowledge/webinars/detail/cham...

Quote (lexpatrie)

I've seen a lot of people here post about an obvious punching shear problem, but I've not seen any load calculations or strength calculations, as I recall.

That same presentation has several other punching cheer calculations throughout the video, one is near the 33-minute mark. Punching sheer calculations are not particularly complicated to do, they've been in the ACI 318 standard since at least the 1970s. If you are looking for punching shear design calcs, they are quite simple to do yourself (as a structural engineer) using the original design information provided by the city of Surfside and ACI 318.

Quote (lexpatrie)

Regarding the "engineer" in the 1990s, was there actually an engineer there?
Yes, see the 9:30-mark of that same Matt Fadden presentation.

Quote (lexpatrie)

As to the plausibility of Morabito being totally unaware of s punching shear issue,
I wasn't implying that Morabito did not understand punching shear as a structural mechanism (as I had even referenced the fact that they had punching shear design calc printouts in their file). I hope it was obvious, but I was referring to the fact that Morabito failed to identify the punching shear design flaw at the critical columns of the pool deck at Champlain Tower South. I definitely wasn't talking about the Dolphin Towers Condominium. I was also referring to the fact that they failed to identify that the distress they observed at the planter was due to deck deflections from punching shear (see the 17-minute mark of the Matt Fadden presentation I linked).

I hope this helps, please let me know if there's anything else you don't understand.

RE: Miami Beach, Champlain Towers South apartment building collapse, Part 19

What I said above was that I've seen a lot of claims about punching shear, I've not seen anybody post an opinion on punching shear along with their own calculations on it. They're supposed to do the calculation, not just, as you say, conjecture, an opinion should be supported. That's on the person giving that opinion, not me. I haven't seen that.

The punching shear calculations presented by WJE are along column line T. This area does not appear to have failed during the collapse, at any point.

"WJE was retained by attorneys representing the condominium association to determine the cause of the collapse and provide litigation support."

What I'm (still) getting at is, even at the 33 minute mark, there's no calculations I've seen by somebody (here or elsewhere) putting forth the opinion there's a punching shear problem where they think failure initiated or where failure occurred. Unless I understand WJE wrong, their calculation actually shows the punching shear issue on the pool deck was not predicted via the loading at the time of the collapse. It fails on paper under the design loading, sure, but which loading are they actually claiming there, the original design or the 1996 one? From 13:52 in the video, it looks like there's a planter "as designed" in that area.



They also mention, at 30:54 "current research" indicates factor of 4 may be unconservative for lighter reinforcement ratios. That's not something you can put onto Morabito, the original design engineer, or the 1996 guy. Too bad they don't cite a reference....

What I think gets missed here is these investigations have more-or-less infinite budgets ( there was that comment about some intern spending a week finding stuff in videos that were posted online, locating columns, [let's just skip the whole direct supervision aspect for a moment] for example), and there is a lot of scrounging after the fact that turns up information nobody had at the time. While there are dozens upon dozens of permits disclosed by the city, that sort of information might not be at the hands of a recertification engineer, typically. They also potentially have access to things we don't have, i.e. actual concrete strength, changes to cover versus the drawings, depth of reinforcing, evidence of carbonation and/or corrosion, etc. Th investigation also has the benefit and hindrance of hindsight, the building collapsed so there must be a problem here...

While the difference between the 2020 photo and the photo closer to the collapse show distinct differences, was that photograph even provided to Morabito? Or did they take it?

I am not deeply versed in the Morabito Phase IIc drawings (issued about 2 months before the collapse, April 27, 2021, collapse on June 24, 2021), but the area people like to discuss most (including your green cloud) is the pool deck that's south of the east wing of the building, where there's no modifications being done in 2021. It looks like the drop caps are over on the West side of the building, as you and WJE both mention, where changes are being made (a new ramp?). The drawings supposedly show drop locations on S2C-1.0 but the section 3/S2C-2.9 isn't specifically anywhere on any of the drawings, it's just referred to via 4/S2C-2.3...

Even so, the issue with the pool slab in the SE corner is modified by another engineer as you now mention. This doesn't seem to have been mentioned in the first 1-18 parts of this thread. WJE redacted the firm involved, but it's public record.



I've added some underlining, please note this is the current language. 2021.

You can track this back to 2013, if you'd like: structural-recertification.pdf from Archive.org, 2013, the language isn't all that different.

The Surfside document archive is here:
https://surfside.one/public-records-search/

RE: Miami Beach, Champlain Towers South apartment building collapse, Part 19

Lex, I wonder if the 1990’s pool deck rennovations engineering firm was a defendant in the litigation? They seem more directly liable than a lot of defendants?

The link to public record is a very long list to go thru to find the 1990’s document on the patio deck. Would you mind uploading it to this site, to save folks a lot of time or provide searchable information that can be used on Surfside’s public record site to find where it is buried?

There was no standard system used in the uploading of the documents, other than random chaos.


Thank You

RE: Miami Beach, Champlain Towers South apartment building collapse, Part 19

Do a text search for for concrete structural repair...... it's near the top.

As far as the 1996 engineer, not that I know of. If one presumes there's a 10 year statute of repose, they are perhaps beyond the date by 2021. Typically in civil litigation as many parties as possible are identified for the initial filing, but sometimes there are "john doe" defendants that are placeholders for people/firms who have not been identified.

I would also point out there have been no disciplinary actions involving anyone.....

And yeah, the documents aren't sorted and the dates given are I believe upload (or perhaps scan) dates. I think the city gave the entire file to somebody who sat in front of a document scanner and they processed them top to bottom. I suppose that implies the file wasn't all that sorted, but it's also possible the files came from multiple sources and they just got processed in the order they appeared, letter size going first and large documents being perhaps outsourced to a FedEx copy shop, if they don't have one in the office. Or some of the more recent ones were scanned as part of a paperless process..... It's possible the files themselves have dates they were created that differ substantially from what appears to be an upload date, but I've not gotten curious about that. I'm not convinced metadata dates don't change sometimes if you upload/download things, like if it's the "date created" on my computer, rather than the date the document was created. I'm not a computer forensics person, by trade.

As a side note, (I haven't watched the whole seminar, looks like you can get 1 PDH out of the deal if you go through the appropriate portal) the punching shear calculations from WJE use a phi of 0.85, (which goes with load factors of 1.4D+1.7L, I suspect). There was some brief mucking about with shear phi factors a while ago (2000?). [ I think I came up with 154.6 kips, so that's pretty close, but it did require an email... as a side note, I'm a bit surprised that alpha plays relatively little role in the punching shear strength as the other two equations box it in pretty tight, it looks like the alpha equation usually governs, but an interior column is at best 20% stronger than an edge.]


Source: ACI 318-95 (not the right code, but it's something)

I don't have quite the right ACI 318 for this one, I've posted links to a few of them that are in public domain (archive.org) over in the FAQs for concrete.

Also, that read of the 1996 letter, to me, suggests the repairs performed were spalled concrete on the bottom of the pool deck, and the WJE seminar seems to suggest they think the topping slab was original and the original engineer (Brietermann) knew about it. Not convinced there is much foundation for that particular claim, but that would suggest the 1996 person had no way of knowing there was extra load on the pool deck, at least not on first glance.

RE: Miami Beach, Champlain Towers South apartment building collapse, Part 19

Lexpatrie -
I'm happy to see you have come a long way from telling me I was inaccurate and errantly claiming I didn't understand the Morabito repair drawings. Though, I see you still are a bit confused and have some more questions, no worries I got you.

Quote (lexpatrie)

I've not seen anybody post an opinion on punching shear along with their own calculations on it

You then literally post a photo of WJE's calculation summary. If you want the math spelled out, I worked up a quick Excel file for you to see below.



Quote (lexpatrie)

The punching shear calculations presented by WJE are along column line T. This area does not appear to have failed during the collapse, at any point...
Unless I understand WJE wrong...
You must understand WJE wrong, their entire presentation focuses in on K13.1. it's even on the screenshot you have. Their calculations are not for column line T?
Based on the label on their table and their discussion, the "as design" column calc is back in 1980 utilizing calculations from ACI 318-77. For their "at collapse" calculation, their dead load includes the weight from the 96 renovations.

Quote (lexpatrie)

"current research" indicates factor of 4 may be unconservative for lighter reinforcement ratios. That's not something you can put onto Morabito, the original design engineer, or the 1996 guy. Too bad they don't cite a reference...
There are actually number of publications about reductions in punching shear under high sustained loads, especially in columns with low fluctual reinforcement (since punching shear is actually flexural behavior). One of the main researchers on the topic was published in 1960 by Rüsch. I included that reference in my calc for you.
The reduction in the constant for Vc (4 to 3) has nothing to do with the work the engineer should have done. That is a failure predictive capacity calculation by WJE to explain the trigger of the punching shear under essentially a non-live load condition.
However, keep in mind Morabito, the 96 engineer, and the original engineer would have been required to utilize the design equations. Had they done that, they would have seen that it was 72% above what the Code would have allowed (using a factor of 4 and no construction errors). Further, it would be worse than 72% if you included the weight from 96. So if Morabito had checked this, or had recognized that the photos they took of the planter were evidence of a fairly far progressed punching sheer failure (WJE says in the presentation that Morabito was the firm that took the pictures of that plantar distress), they would have figured out there was a major problem around k13.1.

I recognize that Morabito wasn't required to verify the original design during the first pass of an assessment. As I mentioned, I don't think they did a particularly poor job, and it's much easier in hindsight to recognize the punching shear problem wasn't just a planter problem. However, had they said, "Hey it looks like the deck is deflecting and is resulting in distress to the planter above" they probably then would have checked to see the demanded capacity of the column, which even if they ran it under design loads (which would have been the most likely thing to do) and they used a factor of 4 for their punching sheer calcs (something very reasonable for them to do); they still would have seen that they had a major design problem. I've mentioned several times in this thread that over the majority of the life of the structure evidence of the punching shoe problem would not have been visibly evident. However, Morabito happened to take pictures of the planner before and after the deck deflection started, again which is a very late mechanism (close to collapse) in the progression of a punching shear failure.

What I'm saying is, mistakes by engineers are the primary sources of the collapse; not failures by contractors; not failures by the association; not failures by inspectors. The original engineer designed it with 72% less capacity than it was minimally required to have by code; the 96 engineer, did not check the capacity of the deck to column connections, even though they were adding substantial weight.; and the recertification engineer, failed to identify evidence of a problem.

The first two engineers are primarily culpable, but any of those three engineers could have prevented the failure.


(A quick aside, that language from Miami-Dade regarding "time tested" is simply not true, its absolute nonsense, but that's a topic for another day.)

RE: Miami Beach, Champlain Towers South apartment building collapse, Part 19

Quote (Dave.Smith.NYC (Structural))

that language from Miami-Dade regarding "time tested" is simply not true, its absolute nonsense, but that's a topic for another day.

It may just be as relevant as anything that has been discussed. The thing that seems ambiguous, is regarding the qualification that the loading conditions and patterns have not changed and that such can be determined without verifying the original design. It sounds like white wash to me. In and of itself the policy might be cited as a contributing factor.

RE: Miami Beach, Champlain Towers South apartment building collapse, Part 19

Dave, read what I'm writing versus skimming, deciding what I'm writing and then "refuting" it and saying I'm "confused." You can stop that now. Thanks.

So we're clear, I still think you're inaccurate, you've just glossed past it and declared mission accomplished. Maybe you have documentation I don't know about.

You have an opinion, it's on you to present evidence for it. You are expected to lay the foundation for your opinion. You have the burden of proof here, it isn't my job to disprove whatever you write, it's on you to prove it, it's actually on you to have proof before you speak, i.e. be objective. Convince me. Convince others, should they choose to engage with your ... tone. Show the connective tissue.

You think there's a deficiency in the design, fine, but you're supposed to produce the calculations (or at least the results), you're supposed to find the supporting information, not me, not anybody else.

When I said I hadn't seen any punching shear calculations in the thread here, then you seize on this as somehow like it's me being deceptive, or confused, and point at the WJE seminar, which I hadn't seen. Just. Not. The. Case.

When I talk about calculations, I mean the full calculation, as in the level of detail that would be in a calculation package, not the result only or a demand/capacity ratio that's quite fuzzy on what exactly was done in the calculation (WJE has presented the results of their analysis, not the full calculations that produce the analysis, you can recreate them, at least potentially, provided you get the right phi (0.75 for shear in ACI 318-77), the right depth, the right strength of concrete, the right load factors and loads, and you correctly interpret when they are not using the phi or load factors, which cover they are using, etc., so can I, but they've not published them, nor has anybody else, up to now, as of your post like yesterday), that's why I said "I haven't seen any calculations".

This is what you said earlier:

Quote (Dave.Smith.NYC)

I saw the notes from Gary Klein that Morabito had in their file structural analysis software data printouts that indicated punching shear deficiencies with the original design. I have not seen any information regarding why Morabito didn't take action regarding these data printouts. It's possible, but they were not using the software with that purpose, and simply did not look at all of the data printouts, I have no idea anything I would say would be conjecture.

You're apparently referring to the WJE slide in the presentation as "notes from Gary Klein", rather than some published notes elsewhere. Fine. That isn't how I'd describe a slide from a presentation, I thought you were saying there was something published elsewhere.

So, just to clarify, here's what I wrote:

Quote (lexpatrie)

The punching shear calculations presented by WJE are along column line T. This area does not appear to have failed during the collapse, at any point...
Unless I understand WJE wrong...

It's clear that I'm talking about Line T. You were talking about what Morabito had. That's where WJE presents Morabito's output. You were talking about Morabito there. That's what I'm responding to.

Quote (Dave.Smith.NYC)

You must understand WJE wrong, their entire presentation focuses in on K13.1. it's even on the screenshot you have. Their calculations are not for column line T? Based on the label on their table and their discussion, the "as design" column calc is back in 1980 utilizing calculations from ACI 318-77. For their "at collapse" calculation, their dead load includes the weight from the 96 renovations.

I don't understand WJE wrong. You're not understanding what I'm talking about and skipping over what I wrote.

Again, I'll say it again, the calculations you were referring to, the ones WJE says Morabito had, and I'm talking about in the quote above, is for Column Line T. This is not where anyone has suggested collapse initiated. I'm talking about this because you mention Morabito had these calculations but didn't fix the pool/plaza deck. This is inaccurate. The calculations they had were for Line T, where there's modifications taking place, and Morabito reinforced the structure.

You think you're catching me "confused" but that's not the case, you're narrowing your interpretation to something that fits your view so you can argue it. This is a discussion, not an argument. You have a coherent paragraph here, "Morabito had in their file..... Morabito didn't take action...." what's being misrepresented here is WJE says Morabito had calculations for Line T, and there is reinforcing on the Phase IIc drawings in this area (you show it in your diagram, when you responded to me, the backwards red revision cloud). This whole paragraph is demonstrably false, as written. What I guess you did is jumped to another discussion entirely after that first sentence, which was about Line T, and now are claiming Morabito ignored a punching shear deficiency in the plaza that they had in their calculations. This doesn't seem to be anything WJE said, and it doesn't appear to be anywhere in the discussion here, or elsewhere, so please present your source, or clarify. As I see this now, this is either careless writing or an error in your thinking, or, as you say, conjecture. I haven't seen anybody say Morabito had calculations for punching shear in the plaza/pool deck area.

I guess I'll just start over from the top. There's little point discussing your latest rather condescending post when 80% of the erm, "discussion" there stems from misunderstandings or misinterpretations of what I wrote before. Despite what I said, I'm going to put forth my findings that to me, pretty clearly contradict many of your assertions.

Quote (Dave.Smith.NYC)

Well for the engineer in the '90s that added additional deadload (sic); that action would have required them to analyze enough of the existing structure down to grade to satisfy that the existing structure could satisfactorily carry the additional loads. If that analysis was performed correctly, it would have included the punching shear check at the deck to column connections. That check would have identified a gross under design (especially relative to prescriptive code requirements) and likely would have triggered temporary shoring and strengthening to increase the punching shear capacity at the columns.

This is a nice, convenient, and comforting thought, but I'm not remotely convinced it's accurate. I haven't seen anything definitive about added dead load on the plaza, not that I've read all 18 sequences of the discussion here, or read all the permit documents, but I don't recall seeing that. WJE showed in their slide:


Source: WJE 9:13

I'm not going to name the 1996 engineer here, mostly because they appear to be still alive, but also because WJE blurred out their name. I don't know why exactly they did that, but fine.

While WJE claims "added dead load" e.g. paver installation, the document they blur out (the engineer's certification letter on the repairs in the parking garage) says nothing about paver installation. So was the 1996 engineer aware of that part? It's not in their certification. The document WJE blurs out and obscures doesn't mention paver installation, so that's a false accusation already. The document they reference sure looks like that engineer's involvement was constrained to just the parking garage. There is no definitive proof that engineer knew of the added weight, particularly in light of the repair they certified is being done is in the parking garage. The permit does list the engineer and disclose paver installation.

Anyway, if you are aware of some document, somewhere, indicating dead load being added, proving that the 1996 engineer knew about it, please present it. Your desire to lay this at the feet of what appears to be a spalling repair in the parking garage, well, I don't see any evidentiary support for it. That seems really inaccurate and unsupported by any documentation I've seen. Is this your opinion based on independent verification, or is it based on the say-so of WJE?


Source: WJE 9:30

This is incredibly deceptive on WJE's part. Flat out. The only documentation on the engineer's involvement indicates structural concrete repair in the parking garage, then they put up a slide saying "under the supervision of an engineer, Paver installation", and put the certification language that directly contradicts their claim, then throw up a cross section that shows the pool deck, where it's not even remotely clear that engineer was involved.

[Side note regarding the truth, from 1931.]

This is what an infinite budget review of documentation produces... an intern spends a week mapping parking spots to columns in videos online [with perhaps zero involvement of the professional engineer in responsible charge] and nobody can be bothered to read a 23 page document. And then somebody watches the presentation and takes it as fact without any review.



WJE says there was a layer of sand and pavers "added" (9:25) but WJE doesn't present a document showing that (the bundle of pages with the 1996 engineer does mention interlocking pavers, but again, that document is a permit document from the contractor, pretty clear the engineer had no involvement in the preparation of that document). Just because they put the engineer's name on the permit doesn't mean the engineer is on for the full scope. I'd be surprised if the engineer ever saw that permit application, and their certification letter certainly does NOT reflect the purported scope of work the contractor put in the permit (no mention of planter waterproofing, no mention of paver installation being "done in compliance" with the SFBC.

And if the engineer is supposed to be certifying the plaza and the paver installation, the city didn't make that happen. So, yeah.



The satellite imagery isn't of a quality to show pavers or not prior to 1996, even if it were better quality distinguishing mortar set tile versus interlocking pavers from a satellite photo seems a bit of an adventure. Still, it seems a bit odd they would be added and there's no documentation on it. What if there were pavers and sand there prior, and the repair work took portions of it up to repair waterproofing? The documents show pavers, sure, but there's no indication the engineer knew about it.

The engineering certification I looked at mentioned a spalling repair of 20 ft2 on what sounds like the underside, where exactly is not stated, it says "waterproofing of the deck" and doesn't give any column line references and there's no map. It doesn't mention adding sand and pavers, either. One might be tempted to presume it was the plaza deck, that seems reasonable, but that's not actually in evidence (In fact, the March 22, 1996 letter from Western Waterproofing says "concrete structural repair in the parking garage", and goes on to identify the person and say they've been retained "to do the inspections and supervise the project").



There's a mention of waterproofing in the engineer's certification, but that would be above the topping, would it not, and given the spalling is in the parking garage, wouldn't the waterproofing be there as well?

Both the pool deck and the parking garage (from the Morabito cores) have a topping slab (according to WJE 12:06). Wouldn't the waterproofing layer be atop that?

Now to the unfounded allegations/speculation/conjecture:

From the WJE presentation, they think the original designer knew about the topping slab. There's no evidentiary support for that, but they think the original engineer (Breitermann) knew about it (12:40). No facts in evidence to support that, that's speculative, but fine. The other explanation is they didn't know and the contractor added it, and/or the Architect knew and authorized the "add" but didn't bother to inform the engineer. Or the Architect ordered it, or the contractor added it out of the goodness of their own heart for no obvious reason (rather unlikely given the cost), but didn't they have an on-site mixer? (I'm going to point at Station Square, 1988, where the contractor added a lot of concrete weight to an already not-great structural design, and it collapsed on opening day, the engineer (and maybe the architect) were unaware of the added weight, the engineer understood the added width of the walkway was to be done with extra insulation). I don't think anybody involved in this project is alive, not the original project.

If the topping slab is already there in 1996, under a mortared down tile, how's the second engineer supposed to know it's there? When the architectural/structural cross section shows mortar and tile and concrete? I'm not even sure the 1996 engineer had any of the drawings, nobody has said that, either.

Then there's sand and pavers. The 1996 work WJE didn't really demonstrate anything at all as to what was done and where, unless you're counting what could be replacement pavers, or that the engineer was never aware of the sand and pavers, or was even involved in the plaza/pool deck at all. Considering the level of reputational damage being levied at the unnamed engineer, this should have had much much more evidentiary support.

Without conceding the hypothetical (i.e. the 1996 engineer knew about the added weight of the pavers):

There would be no particular reason for a structural analysis when the pavers are being removed and replaced with similar weight items, particularly if there's no knowledge of the (not designed for) topping slab. It does appear the sand and pavers were added at this time, the extent isn't clear from the permit.

Even if the 1996 engineer knew there was a topping slab, I'm not convinced that would be enough to trigger an engineer to run calculations. If dead load is being added, I would like to have seen calculations, but I'm not convinced anybody in 1996 either knew the topping slab was added and not designed for, or that the engineer was aware of the added sand and pavers. It looks like the City was aware of the interlocking pavers being added, that's about it, they might have missed there's a parking garage under it, at which point they would be unconcerned with "adding" pavers to a slab on ground.

There isn't definitive documentation either way that I've seen. It seems like sand and pavers were added, but it doesn't seem like the 1996 engineer knew about it, (the certification is for the spalling repair, in the parking garage), and if they did, it's possible they did check the punching shear and it worked because they didn't have the topping slab in the calculation, because they didn't know about it, and because they'd have used the cover "as specified".

Quote (Dave.Smith.NYC)

I saw the notes from Gary Klein that Morabito had in their file structural analysis software data printouts that indicated punching shear deficiencies with the original design. I have not seen any information regarding why Morabito didn't take action regarding these data printouts. It's possible, but they were not using the software with that purpose, and simply did not look at all of the data printouts, I have no idea anything I would say would be conjecture.


Source; WJE seminar, 14:50

According to WJE the software is Sp-slab, (formerly ADOSS), it's possible this isn't using the "as-built" phi, for one.



The shear calculations you say Morabito "had" were, as I already said, NOT on the portion of the building that failed (presumably the plaza, per WJE). WJE presented analysis results (from Morabito) on Line T. You keep claiming "indicates punching shear deficiencies with the original design", this is not a line that failed, and as far as anything I've seen, that area did not collapse. It's on the far West side of the building where the building did not collapse (until it was intentionally demolished). This Line T is checked, for a changed condition that Morabito is analyzing, because (I think) they're cutting in a new exit/entrance to the below grade garage. They are doing these calculations due to the changed conditions, i.e. redesign, not as part of recertification. As far as recertification goes, this is unnecessary. The work is being folded in with the recertification. With the changed support conditions, Morabito appears to have performed a strength check, and reinforced it for the changed loads, hence the drop slabs in this area. Also note there's an unbalanced moment and a gammav, so this is not a "pure" punching shear check.

What I particularly take issue with is your claim:

Quote (Dave.Smith.NYC)

I have not seen any information regarding why Morabito didn't take action regarding these data printouts. It's possible, but they were not using the software with that purpose, and simply did not look at all of the data printouts, I have no idea anything I would say would be conjecture.

Unless you jumped topics mid-paragraph, or I missed WJE saying there are Morabito calcs for the plaza/pool, this is really misleading and inaccurate. In the previous sentence, the data you are discussing is for Line T, in your later post you show where there's column/slab joint reinforcing on Line T. This is where Morabito had calculation results showing a punching shear deficiency (whether it's "as designed by Breitermann" or due to changed conditions nobody has said. Morabito took action on the area they identified as needing reinforcement on Line T. So they did take action.

RE: Miami Beach, Champlain Towers South apartment building collapse, Part 19

AS you would expect, Florida pased new laws and regulations that now require the condos within 6 miles of the ocean have routine inspections and require the condo HOA's to provide sufficient cash reserves to implement all fixes that are recommended by the inspectors. Those requirements have led to huge increases in condo HOA special assessments, and most owners cannot afford the new fees. It implies a lot of condo associations will default and the buildings will either be sold at a discount or demolished.

As I recall, there is an alternate type of concrete/ stucco that is essentially impervious to chloride migration to the rebar- it is a type of geopolymer cement, and that 15 yrs ago the florida DOT had tested adding a geopolymer stucco to the concrete based bridges that span salt water creeks .

"...when logic, and proportion, have fallen, sloppy dead..." Grace Slick

RE: Miami Beach, Champlain Towers South apartment building collapse, Part 19

Here is a link to one of the few companies that sell geopolymer stucco in the USA: https://www.geopolymertech.com/st200-stucco/. It has much lower porosity than portland cement stucco and might achieve adequate mitigation against chloride corrosion to the embedded rebar.

"...when logic, and proportion, have fallen, sloppy dead..." Grace Slick

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