Miami Beach, Champlain Towers South apartment building collapse, Part 13 44

One thing no one has mentioned is that when a contractor last year took those core samples, it appears they cored right through rebar. I always thought this was a no-no. In fact, Surfside sent out guidelines to building owners stating to use GPR (Ground Penetrating Radar) first before taking core samples, to avoid hitting rebar. It is no strange coincidence to me that the core sample which penetrated the rebar was taken just inches to the left of column M11.1, right next to the planter box. You have seen me point out in several of my videos since June about how they left that core site open with Bob's barricade there, and in some other MLS photos, seems like no covering was ever put back on the 3' x 3' exploration site. these core sites are required to be filled back in and returned to the state they were in before the sampling, pretty much the same day if possible.

Basement Floor (lowest level below-grade)
o Perform GPR (ground penetrating radar) to determine slab thickness and to locate
reinforcing steel, if reinforced (conventional slab on ground or reinforced slab on
ground).
o, Take one set of three concrete cores (after GPR to avoid reinforcing steel) for
compressive strength testing per AC! standards and one core for petrographic
examination per ICRI standards. Repair cored holes in accordance with ICRI industry
standards.
o GPR column for vertical reinforcing steel and lateral ties (measuring spacing) for the full
height of that lift. Verify vertical column reinforcing splices,
o Take one VA" diameter maximum 3"-depth core In column (after GPR to avoid
reinforcing steel) for compressive strength testing per ACI standards and petrographic
examination per ICRI standards. Immediately repair cored holes in accordance with ICRI
industry standards.

Re theories and mechanisms lost to the voluminous scroll: built us a spreadsheet to capture views succinctly in one place, but not many people have availed themselves. She may have locked it now but you can request access within the document by pulling down the view only button at the top. For Charlie not to spend the rest of his life relaunching this thread I suggest we re-engage with this, if Maud has not given up and gone fishing long ago.
Link

Edited to add

Jeff Ostroff said:

Rebar damaged by cores

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Case in point, that topic has come up a few times, but you'd have to dig back now to see it.

Its not unusual for a core sample to break apart when drilling it. Especially if you were to hit rebar on the way through it. The broken core samples tend to break right at the rebar.

This has not been my experience... generally cores with rebar come out intact, and generally not fractured at the location of the rebar. If they do break at the rebar, the halves have neat surfaces. It may have been that due to corrosion issues and the expansion of the corrosion products that the concrete was compromised at the junction.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

Per the Miami Herald Editorial Board, Florida needs state-wide condo inspection and reserve fund regs to help prevent another CTS. We don’t know what caused Surfside collapse, but we know something else that’s gone wrong | Editorial

In that environment, 40 years is too long... more like every 10 years. The engineer also has to note if there is anything that requires immediate or very near future repairs and this has to be on file with the municipality.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

Jeff Ostroff said:

Surfside sent out guidelines to building owners stating to use GPR

Click to expand...

The requirements you're citing were in the "Properties East of Collins Avenue Structural Assessment Recommendations Letter" dated July 7, 2021, advised by Kilsheimer in the wake of the CTS collapse. I don't know what Surfside's requirements for core samples are/were in the period before June 24, has anyone been able to find that? Something tells me that common procedure was not so exhaustive, at least in practice...and even if that was the protocol, I highly doubt it was ever enforced. It obviously wasn't here, as clearly shown in the engineer's own documentation.

From the document "20201014bodminutesapproved", per Morabito's memo dated October 13, 2020 (Re: Champlain Towers South Condominium – Phase IIA, Summary of Work Performed) "At completion of the investigative work CPR restored each exploratory (and core) location back to its original condition." The attached and marked up plan sheet S2A-1.1 is more detailed in the scope for each core sample site, GPR wasn't mentioned. I'm not sure if that's what the memo refers to when it says "The
results of exploratory demolition and the additional core work are summarized in the attached “CTS Test Probe
Notes” file" or if that's a document that hasn't been released? I don't recall having seen it but that doesn't mean much.

The rest of the notes from S2A-1.1...I can't extract the individual sheet at the moment, I can do so later on today for anyone who doesn't want to go on a pdf scavenger hunt.

AusG said:

…built us a spreadsheet to capture views succinctly in one place, but not many people have availed themselves.

Click to expand...

Thanks, AusG. I was about to bring this up again myself. We have a self-serve repository that few have used. If more would use it, it would act as a summary of the lengthy discussions on these many pages. Anyone can view the spreadsheet. And anyone can use the entry form to add to it. The only thing anyone needs me for is to sort it, as I am the only person with edit privileges.

This Google Form Engineering Input Form automagically writes to the CTS Collapse spreadsheet!

Procedure

1. Complete and submit the Engineering Input Form
Screen Name
Type
Sub-type (free form text entry)
Theory/Hypothesis <short description>
Proven Evidence
Possible Evidence Not Yet Proven
Argument Against
Notes/Links


Tip: Check the spreadsheet to see if your Theory is already listed. If it is, use the same Type, Sub-Type, and Theory/Hypothesis so that sorting will place your entry by the previous listing. There is no limit on how many listings a particular theory may have.

2. Review the CTS Collapse spreadsheet to see your entry/entries and everyone else’s entries.


We will use the Type/Sub-type fields as organizers. This will allow us to sort the spreadsheet so that related items will appear next to each other. This will be more efficient than human intervention to organize separate tabs, although we could also do that after we end submissions.

Jeff Ostroff (Electrical)7 Sep 21 05:47 said:

One thing no one has mentioned is that when a contractor last year took those core samples, it appears they cored right through rebar. I always thought this was a no-no.

Click to expand...

... was hashed out long ago here. That's why we post post links to the previous parts of this thread at the top of every part!


SF Charlie
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AutisticBez (Computer)7 Sep 21 07:33 said:

Its not unusual for a core sample to break apart when drilling it. Especially if you were to hit rebar on the way through it. The broken core samples tend to break right at the rebar.

Click to expand...

Dik has already spoken to this. It's the quality of the break that tells the story. This is not a new break caused by drilling, it's an old break (potentially caused by rebar expanding, due to salt water intrusion.) and since it appears to have happened at most of the cores, it leads to the suspicion that a lot of the structural pool slab delaminated.


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The green thing in the Tiktok pic looks like the patio chair and green cushion from unit 111.

In the case of that one core that I had brought up that was next to the planter, that likely has very little to do with salt water intrusion in fact probably close to zero. If that is on the pool deck there's no soil under it there's no way for saltwater to get to it, it's strictly from rainfall and water pooling on the pool deck over the years. I would also really love to know where it was that they originally made repairs in 1996, that morabito found in 2018 that could really give us a clue as to where there was some weak and concrete that would be much more weaker than other areas around it. Because in 1996 they were claiming they had to fix almost 500 square feet of cracks which is amazing after only 15 years of life.

Cores taken from around or under planters would be repair work they show, and very minimal original concrete.

Perhaps it's not delamination, but just lack of adhesion of repair layers.

*shrugs*

Precision guess work based on information provided by those of questionable knowledge

demented said:

Cores taken from around or under planters would be repair work they show and very minimal original concrete.

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That is likely untrue. Because from what we can gather they did not remove any of the concrete from the pool deck, there were cracks all over the place, that in 1996 they repaired the concrete using epoxy injections. This apparently was done by somebody that did not know what they were doing, and they actually left several of the injection ports into the ceiling and never sanded them down and primed and painted or anything to help seal it up afterward. And so these often left to even more cracks developing. but we have not seen any evidence anywhere that suggests that they removed any of the original pool deck concrete and replaced it. Do you have any information on that? Are there any permits that were pulled or any drawings that show the work that they were supposedly doing on that?

Yes, drawings, permits, engineers notes, inspections, inspection notes, BOM's, ect.

It's been gone over in threads past. It was a fuckerclust of pumped and bagged concrete in the 9" slump range, repair mortar, and epoxy/foam injection. Rebar inspection and replacement too.

Precision guess work based on information provided by those of questionable knowledge

arbitraria (Civil/Environmental)7 Sep 21 14:10 said:

"Properties East of Collins Avenue Structural Assessment Recommendations Letter" dated July 7, 2021
From the document "20201014bodminutesapproved", per Morabito's memo dated October 13, 2020 (Re: Champlain Towers South Condominium – Phase IIA, Summary of Work Performed)

Click to expand...

SFCharlie (Computer)(OP)7 Sep 21 04:56 said:

I could not find:
"Minutes of BOARD OF DIRECTORS MEETING held Wednesday, October 14th, 2020 at 7:00 PM"
in the City of Surfside Archive, but NPR had a link to the .pdf

Click to expand...

in a memo sent to the condo board in October 2020

My trick for getting a single page of a pdf is to print the page with the printer set to: "Microsoft print to pdf"
Please find attached:
Minutes of BOARD OF DIRECTORS MEETING held Wed October 14th, 2020 at 7-00 PM sheets 43,44 of 83.pdf


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Jeff Ostroff said:

In the case of that one core that I had brought up that was next to the planter, that likely has very little to do with salt water intrusion in fact probably close to zero.

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Aren’t any exterior surfaces where water pools or accumulates in coastal environments subject to salt water intrusion? It would seem to me that the air there is somewhat laden with salt (sea spray) and anywhere it does not runoff from, it will be concentrated with every wetting and drying cycle.

Jeff Ostroff (Electrical)7 Sep 21 15:58 said:

In the case of that one core that I had brought up that was next to the planter, that likely has very little to do with salt water intrusion in fact probably close to zero. If that is on the pool deck there's no soil under it there's no way for saltwater to get to it, it's strictly from rainfall and water pooling on the pool deck over the years.

Click to expand...

Jeff, It's a block from the beach. You know, I know, everybody knows, salt air plus rain equal salt rain. You can Taste it in the air. It corrodes aircraft at Miami International, a lot farther inland than this...
The ocean runs in the streets...
Nop, no flooding here:
Thursday Night's Rain Caused Street Flooding On Miami Beach
...ever heard of storm surge?


SF Charlie
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