Miami Beach, Champlain Towers South apartment building collapse, Part 19 27

[SFCharlie]

A continuation of our discussion of this failure. Best to read the other threads first to avoid rehashing things already discussed.
Miami Beach, Champlain Towers South apartment building collapse
Miami Beach, Champlain Towers South apartment building collapse, Part 02
Miami Beach, Champlain Towers South apartment building collapse, Part 03
Miami Beach, Champlain Towers South apartment building collapse, Part 04
Miami Beach, Champlain Towers South apartment building collapse, Part 05
Miami Beach, Champlain Towers South apartment building collapse, Part 06
Miami Beach, Champlain Towers South apartment building collapse, Part 07
Miami Beach, Champlain Towers South apartment building collapse, Part 08
Miami Beach, Champlain Towers South apartment building collapse, Part 09
Miami Beach, Champlain Towers South apartment building collapse, Part 10
Miami Beach, Champlain Towers South apartment building collapse, Part 11
Miami Beach, Champlain Towers South apartment building collapse, Part 12
Miami Beach, Champlain Towers South apartment building collapse, Part 13
Miami Beach, Champlain Towers South apartment building collapse, Part 14
Miami Beach, Champlain Towers South apartment building collapse, Part 15
Miami Beach, Champlain Towers South apartment building collapse, Part 16
Miami Beach, Champlain Towers South apartment building collapse, Part 17
Miami Beach, Champlain Towers South apartment building collapse, Part 18

 

[Sym P. le]

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

 

[ComradeStiv]

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.

 

[MaudSTL]

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.

 

[ComradeStiv]

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.

 

[SFCharlie]

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

 

[lexpatrie]

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.

 

[Sym P. le]

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

 

[3DDave]

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.

 

[Dave.Smith.NYC]

[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.

 

[Sym P. le]

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.

 

[zebraso]

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?

 

[MaudSTL]

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.

 

[stcbus]

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

 

[Murph 9000]

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.

 

[Dave.Smith.NYC]

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.

 

[lexpatrie]

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.

 

[Dave.Smith.NYC]

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)".

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.

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/webin...wers-south-surfside-fl-collapse-investigation

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.

Regarding the "engineer" in the 1990s, was there actually an engineer there?

Yes, see the 9:30-mark of that same Matt Fadden presentation.

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.

 

[lexpatrie]

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: https://www.miamidade.gov/permits/library/structural-recertification.pdf]structural-recertification.pdf[/url] from Archive.org, 2013, the language isn't all that different.

The Surfside document archive is here:

https://surfside.one/public-records-search/

 

[Oops409]

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

 

[lexpatrie]

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.