Miami Beach, Champlain Towers South apartment building collapse, Part 17 14

[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


SF Charlie
Eng-Tips.com Forum Policies

 

[MaudSTL]

The owners of 309 are listed as Nelson A Fonseca (Husband) and Myriam B Fonseca (Wife). If I found the right one, Nelson is CEO of an IT company in Coral Gables, so they are renting 309 to the Longobardis.

https://cdn.theorg.com/fe0b9df1-7c74-46df-a5f0-d9cfb27b33ea_medium.jpg

 

[zebraso]

Is the punchout pattern around column 72/73 indicative of a directional wave of failure?

One of the puzzlements in the photo of that punch out is the way the broken stampcrete at the column ended up. Not to hijack any thought process on the actual slab. I just can't get my head around how the stampcrete passed over or around the bars and ended up so neatly in the front print of where they began. And then compound that with the appearance the the large piece seems as though it was under the rear end of car the whole time. There is an explanation of course. I just can't imagine it.

 

[Sym P. le]

how the stampcrete passed over or around the bars and ended up so neatly in the front print of where they began.

It's all rather magical isn't it. And the clean top bars.

 

[zebraso]

Problem is "magic" is not how we should chalk it up. Anyways, I meant to say footprint and not front print. Must have been auto correct or some other voodoo.

Edit: I think it may have happened that the right rear under side of the bumper would have rotated the stampcrete clockwise over the top bars as it slid downward. Then after it passed the bars the car bumper would have pushed it down under the bars and it fell right back into the hole it came out of. Sorry, I just have to try to make sense where there is none. I just don't know why it took so long to figure out anything plausible. The clean looking bars are probably more concerning then.

Edit: dang I meant left rear. I'm looking at it like a CT scan I guess. (joke)

 

[IanCA]

I would like to reintroduce the image that MaudSTL contributed to back in February.

I’ve mapped the narrative onto IanCA’s annotated drawing for the sake of discussion.

I think it is relevant in light of the recently publicized witness statements from appt 309.

The only thing I would adjust now is to suggest that the loud crash heard at 1:10AM could be a portion of the deck/planter base falling into the garage.

If the deck collapse is progressing from the south to the north this suggests the deck collapse started at or near the southern wall. Other evidence, such as the shape of the collapsed decks and the dust on the column, suggests that the parking deck collapsed before the pool deck.

Longobardi's potential view to the south is much more directly down so I've indicated a potential footprint of view accordingly.

Thanks very much for the helpful images. Another factor I have in mind is that they may well have seen the dust to the south, to their right, because it was clearly reported by other witnesses before the main building collapsed. If they could see a dust cloud to their right and then observed the deck collapsing in front of them and progressing to the left I think that would reinforce their perception of the event and fit well with their reported statements.

 

[Sym P. le]

Unfortunately, basic physics xnays that theory without additional support and once again, that planter is not likely to have the degree of influence that you imagine. It is far more likely that vehicle traffic caused deterioration at the column interface, which suffers from a lack of rebar.

 

[FJBnomics]

Support needed here

We are talking a 2-way reinforced rebar grid slab, and more significant deterioration of structural slab under planters, due to no water proofing membrane under stamped concrete with edge of stamped concrete butting up to Southside planter wall. Then add pool exhaust chemicals mixing in plants and planter soil.

So if slab under planters deteriorated more, it is logical their loss of strength could affect that area more, leaving a cantilevered slab to the North, that at that moment has the N-S grid loads fully transferred to the less deteriorated E-W grid at the point where support is needed that would cause tension break in top of stamped concrete and structural slab.

Seems to fit well within the laws of Physics. Support does not have to be a wall or column directly under break, at a given second or millisecond.

Note E-W rebar grid held longer to West and was unzipped to the West, which is evidence of support provided to cause tension crack in top of slab.

Edit: It also appeared to me in photos, that there was no consistent laying of N-S rebar under E-W rebar. Sometimes it appeared E-W was bottom grid. This would seem to affect how loads transferred, based upon a given initial failure point?

 

[Sym P. le]

I've always understood the laws of physics (mechanics of materials) to be the same regardless 8000 psi concrete or a wet sponge.

 

[FJBnomics]

The other thought is all the flexing of the elevated parking deck has added weakness in specific locations based upon loading of that area, and slab deterioration in that area. So we do not have uniform structural properties in the reinforced concrete structure, which is an unknown variable in equation.

 

[Sym P. le]

Yes but no matter how weak the concrete system is, in order for a downward force to break it, there have to be reacting supports or the system will merely rotate.

 

[Jeff Ostroff]

Here is another photo that I shot at the one-year remembrance ceremony at the Champlain tower South collapse site last Friday morning. You can see just how many round core samples they've taken from the wall of the garage ramp it's amazing they needed to take that many core samples also if you look in the background on the far West side of the site, you can see all of the holes they drilled into the elevator shaft vestibule, which is really the bottom of the giant shear wall.

I also noted in the video the other day about how they've really torn up the bottom of the ramp and there's a lot of sand piled up there now, unfortunately we still need more data all the way unless that is the C and from where they made those big 10 foot square cutouts around the columns M9.1/10 and L9.1/10, and L11.1

 

[Sym P. le]

Drone footage is great for assembling 3D views

 

[MaudSTL]

Psychedelic, man!

 

[Reverse_Bias]

If the security cameras were on around the pool deck, we would have more answers as well. Maybe they were and the investigators already have the info. I can't imagine turning on my phone cam that fast myself.

I meant the building collapse. Another video between the deck and the building collapse of the X11 and X10 stack would be a big help. Adriana Sarmiento's video was shot through the garage gate from across the street (Which I don't blame her for). You can't really tell how far the deck collapse extended from it. Witness interviews don't make it very clear either. Gabe Nir hasn't even stated whether he saw his own balcony collapsed or not as far as I'm aware.

 

[MaudSTL]

Gabe Nir hasn't even stated whether he saw his own balcony collapsed or not as far as I'm aware.

Gabe was in the kitchen and Chani was in the shower when the deck collapsed. Their patio slider was open and dust was rolling in. Gabe felt the floor rumbling and swaying, and rousted Chani from the shower. They both ran to the door of the apartment and looked down the hallway as their mother came charging back from the lobby to wrangle them. Chani famously balked at leaving because she was wearing a robe and had her hair in a towel.

Sara got both kids to the lobby and issued commands to Shamoka while Chani watched the Vazquezes stumble out of the elevator in shock. Gabe went outside and realized that the car park had collapsed and came back in to roust his mother and sister as Shamoka attempted to get the correct address written down so she could call 911 back. After the Nirs and Vazquezes ran across the street, Gabe called 911 and gave them the wrong address while they tracked his location and his mother was hysterically beating on strangers’ doors to warn them about the earthquake. Then the building collapsed.

Gabe has never stated that he looked out the slider or saw the balcony.

 

[Sym P. le]

You can't really tell how far the deck collapse extended from it.

The extent of the damage from the deck collapse and which was recorded by Sarmiento is becoming clearer. The Nir's deck furniture is clearly seen in the garage on the higher resolution NIST images. Also, if you look at the lower 3D image above and the image below, you can see how plainly the parking area slab broke off the step up to the lobby floor level. I suspect the initial deck collapse proceeded all the way to the step at the Nir's sliding door, possibly even resulting in the their storm shutters landing in the garage (which I posted earlier). I'm also working on some photo's of the columns in the lobby parking that I believe are telling. I think the evidence will show what was pointed to in the earliest days, that the pool deck and parking area were inadequate in design, installation and maintenance. I'm starting to think that if they just stopped parking at the lobby level, the building would still be there. More to come. And I do think the authorities are way ahead of us with their evidence. I wish they would show more of their hand.

 

[MaudSTL]

…security cameras…

I thought we had ascertained long ago that the CCTV was stored on media rather than the cloud. If so, I think that if the storage device was salvaged, we would have heard MDFR mention it along with their other feats. And, things being how they are these days, by now some images would have been leaked. In addition, NIST was practically begging for citizen photos and videos. I am guessing they don’t have the CCTV videos.

 

[IanCA]

Yes but no matter how weak the concrete system is, in order for a downward force to break it, there have to be reacting supports or the system will merely rotate.

I am working on a simple animation to try and explain what I have in mind. I hope to post that this weekend.

Thanks for posting the 3D views.

 

[FJBnomics]

In Symp's 3D images, there appears to be different types of failure happening on either side of Column Lines between parking spots 71 and 73. Question is which direction does this say collapse is progressing? One side of column deflection of slab causes draping of stamped concrete, where as the other side just shears cleanly off.

Edit: Perhaps just Lobby step up in slab provided sufficient stiffness to cause shear of slab on parking deck side, once slab was deflected on South side of parking 71/73 columns due to failure progressing from the South to the North.

 

[zebraso]

The point of your arrow looks like it's in the stampcrete, not slab or topping. In other words the stampcrete is sloped a lot there and becoming as thick as the slab towards the E/W planter box. The stamp-crete abuts the step or wall. I mean what do you see there?