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

[SFCharlie]

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

SF Charlie
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[FJBnomics]

Maud, I am thinking first cracking noises may be slab under inner planter wall failing. I think that area drops creating punch shear at I14.1 next while tearing East as well. Clearly later rebar shears at South wall could be gun fire type noise.

There is so much reflected sound in a concrete structure, and shifts in sound as it reflects.

In general though, I think current evidence supports the spirit of witness statements, but very hard to tie exact events to specific statements. Perhaps more thought needed?

 

[MaudSTL]

It’s a theory. We can project logical options that will not pin anybody down.

 

[Optical98]

It's a decent theory, it holds more merit than the pool deck just collapsing on it's own one night.

Are we certain all 3 of the 10.1 columns failed? I thought we'd found some of them (the bases) still upright in later analysis. Just something to double check on.

I agree we need to tie it to the statements as best we can, without suggesting they "didn't know what they heard" etc.

 

[MaudSTL]

I wonder if this new joint protocol will include the Town of Surfside. From the Miami Herald, Parties in the Surfside condo collapse lawsuit could soon gain access to evidence from site.

>>>>>Edit: Here’s an archived version.

 

[MaudSTL]

…thinking first cracking noises may be slab under inner planter wall failing. I think that area drops creating punch shear at I14.1 next while tearing East as well. Clearly later rebar shears at South wall could be gun fire type noise.

Can there be a five minute gap between the planter area dropping and the punching shear that brought down the deck?

We have to think about the loud crash at 1:10 that was followed by rumbling and the deck collapse at 1:15. The tricky part is that whatever happened at 1:10 was not noticeable to the Vazquezes down in the garage right before 1:15. So if it broke through into the garage, it would have to be of limited size.

This level of detail is why I think it’s a good idea to talk about all the logical narratives that could make sense within the context of the theory.

 

[FJBnomics]

Maud, I wish other folks would chime in too. I think it is possible the slab broke under inner planter wall and fell or sagged some distance, prior to progressing further. Perhaps a little time delay?

 

[MaudSTL]

I do too. I come from a field where there’s no penalty for brainstorming solutions. I have the impression that structural engineers don’t feel comfortable doing this.

I was imagining that if the rebar under the inner edge of the planter started failing earlier in the evening, the pull on the slab that ultimately tore it off the south wall could be gradual. At 1:10, some of the the Zone A connections to the south wall could have failed and made that loud crashing sound. The edge of the Zone A slab section could have balanced on the top of the garage wall for five minutes until enough load was transferred that the slab punched through I14.1 at 1:15…and then it all went down fast in the paths we’ve theorized.

Maybe someone else can imagine a different narrative that would make more sense.

 

[FJBnomics]

Maud, I think you have a good narrative, based upon evidence we have. I have a feeling that slab was source of noise heard a day or two earlier as it sagged and cracked.

Why Radio Silence from IanCA?

 

[MaudSTL]

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

==> IanCA, I’ll delete this if you like.

 

[IanCA]

Why Radio Silence from IanCA?

Sorry about that thermopile, I really appreciate all the feedback and ideas. I had other commitments I had to deal with. I am keen to get back to this and will provide specific responses and additional information later this evening. I think all of the additional diagrams and markup add value.

 

[Jeff Ostroff]

Elena Blasser in 1211 heard those cracking sounds between 3 am and 4 am the night before, and remember, what seemed loud and local to her could have been anywhere, as sound travels readily through solid materials.

The sound Elena heard could have originated from the pool deck planter right outside Sara's Unit #111, or it could have been from a few floors below Elena, or because of the solid slabs, it could have been a few units over and down.

Have you ever been in a multi-story building near a railroad track when the train passes by? You can feel the vibration, it travels up the columns of the building and across the slabs.

 

[LionelHutz]

2500HD Duramax. Where's the zoomed in pictures of the fender badges that prove that one? At least post the picture of the amber roof lights that truck would have.

 

[Reverse_Bias]

If the collapse and knocking sounds did start near the back planters on the parking deck it's hard to believe none of these people went out on their balconies to look what was going on until after the collapse. Those planters are at least partially visible from every balcony in this picture and a lot of them are closer to it than the Nirs who reported the knocking sounds.

 

[IanCA]

@MaudSTL @thermopile, thank you for your kind comments.

To simplify the correlation of your detailed theory with the timeline, here is a screengrab of the key perceptions for your convenient reference.

Thanks, MaudSTL, much appreciated. This is helpful and I agree with your later post:

I’ve attempted to map the Parking Deck Failure Theory onto the Witness Observations from the Timeline. Please review and provide corrections to this draft.

I would like to share another observation related to the dust which is mentioned several times in the witness statements.

In several photos, including the one posted by thermopile on 3 Feb at 22 23:35, the column at the transition from the 8-foot wall along the pool deck, to the 4-foot wall by the planter is much lighter in color than its neighboring column to the east, as shown in the cropped images below. Notice the East side of both columns is brown in the first image.

Credit JoeRaedle Getty Images
I first noticed this back on October 30th and it took me until Nov 3rd to come up with a good explanation. I think it is simply dust causing the lighter color, both columns are the same color again in later photos after it has rained. But the dust didn't come from the collapse of the building, because both columns would be equally exposed to that dust. I believe it most likely came from the pile of rubble below the column and was blown vertically by the air being exhausted from the garage as a large section of the pool deck collapsed, coinciding with the air pressure described by Adriana and Roberto at ~1:15. I believe that the air pressure was caused by the rapid reduction in the volume of the parking garage. I don't think there would be as much dust on that column if the failure had progressed from north to south. I suspect the dust adhered to the column because surfaces were wet following the rain the afternoon before. If the failure had happened first near the building then later to the south, dust in the parking garage near the building would have been blown north towards Adriana and Roberto. But they didn't mention dust and it doesn't look dusty in their video. For me, the dust is another big topic in itself. Why was there so much dust? I think it was caused by the chemical action of acids produced by salt and pool chemicals (exhausted in that area) leaching calcium compounds from the concrete (seen forming what appear to be stalactites in the garage tour video - not the cylindrical injection ports with flanges) leaving a very weak powdery concrete behind.

I hope that helps.

I will try to catch up on responses to other posts tomorrow.

 

[AusTony2046]

@Reverse Bias:

Well, it was dark, and looking straight down on a scene where not much horizontal shift had occurred, it might not be obvious from above that anything had happened directly below.

Having said that, I think it likely that at least some of the occupants of the west part of the building were out on their balcony/ies looking for the cause of the "first" crash when the building came down. Perhaps they have been told not to talk to the press?

OT, what is "stamped" concrete and how does it differ from the concrete under the pool deck?

 

[MaudSTL]

I think it likely that at least some of the occupants of the west part of the building were out on their balcony/ies looking for the cause of the "first" crash when the building came down.

The Nirs in 111 were saved by the fact that they were all awake. I think what saved Ileana Monteagudo in 611 is that her balcony door was open when she went to bed. She was awakened by the sound of the deck collapsing.

Many people in Florida sleep with their hurricane-reinforced windows closed and sealing out the sound. The fire department employee watching TV on the 12th floor didn’t hear the deck collapse or feel the building shake…he heard the building collapse and compared it to a jet. The Gonzalezes watching TV in 904 lived by being awake and having incredible luck, not having heard the deck collapse nor having felt the building shake…they started running to the hallway from the bedroom as the building actually collapsed beneath them. What woke Cassie Stratton up in 410 was the building shaking after the deck collapsed, not the the sound of the deck collapse. This may also have been true of others. Adriana Sarmiento says that there were people on the east end of the building who came out onto their balconies as she videoed at 1:18 to see what was going on. She told them to get out, but they couldn’t hear her and were out of time.

 

[FJBnomics]

At least post the picture of the amber roof lights that truck would have.

Lionel

Apparently you have never spec'd and ordered a custom 2500 truck. Those amber roof lights are an option, and not on ever 2500. My son's build to order 2500, does NOT have amber roof lights. Perhaps some states require them, but they are not required by any of the states in our area.

Edit: A quick Duck Duck Go, yields clearance lights are DOT requirement on commercial vehicles 80" wide or wider. It appears single rear axle 2500's are slightly narrower than 80", whereas all dually trucks exceed 80", therefore have cab roof lights.

Except California has rules against cab lights on some 2500's..... Therefore state by state rules under 80".

 

[MaudSTL]

If the collapse and knocking sounds did start near the back planters on the parking deck it's hard to believe none of these people went out on their balconies to look what was going on until after the collapse. Those planters are at least partially visible from every balcony in this picture and a lot of them are closer to it than the Nirs who reported the knocking sounds.

The person I would like to ask is the security guard. No one has ever asked Shamoka Furman if she was able to hear the banging sounds in the lobby. We do know that she heard the loud crash at 1:10. It is my understanding that the sound of rebar breaking travels through the structure more than the air. If that is so, then it makes sense that people on the first floor would be more aware of it. Various early interviews did say that people were used to hearing all kinds of banging from the roof work that was going on. But that would have been in the daytime.What made Sara Nir go to the lobby to complain is because the loud crash occurred at night.

 

[FJBnomics]

IanCA, your concrete deterioration along South wall due to pool chemicals is interesting as to why concrete at south wall perhaps failed from chemical reactions, and perhaps just let go of rebar at first. The pool curb and top edge was rebuilt in the past. Perhaps partly due to pool chemical failure or the fact that they were raising the patio deck height by decking over the old pavers. Lots of poor operational and maintenance decisions going on. BTW, I wish I had worded my radio silence better, as I was trying to thing out loud to brainstorm what I think your complete theory is, and I really looked forward to you either confirming some of my thoughts or pointing us to your complete logic.

I am not an expert in anything, but I have been exposed at a broad band of technical disciplines. Master of nothing, jack of trades sort.

I would like to add that frequency of sound determines transmission thru building materials, and that at lower frequencies standing waves can form that reinforce some frequencies and cancel some frequencies.

Lower frequencies transmit thru concrete type building materials better than higher frequencies.

Edit: IanCA, I believe I am following your logic on initial event under planters at transition between slabs and privacy wall transition.

I am seeing tension reinforcement in bottom of 13” slab not lining up with tension rebar in bottom of 9-1/2” slab, and possibly a construction joint at slab transition.

I will just wait for your complete logic and evidence to flow.

 

[LionelHutz]

Missed my point completely. But why expect any reality to be followed at this point?