Miami Beach, Champlain Towers South apartment building collapse, Part 12 60

[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

SF Charlie
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[Optical98]

Egads...can some of you old timers speak to the site/platform owners about the low graphics?

 

[Jeff Ostroff]

I know the resolution stinks, and I upload high res photos, but it compresses it down. You should be able to click on the photos and have it enlarge.

 

[Vance Wiley]

Apologies - My comment was directed to the bundle of #11s bent over to the left.
The single bar at the first photo looks like a single #4 - maybe a #5. I cannot tell if there were more bars. That is far less than a structural column would have used.
In the second pic the worker is holding a bent bar of similar size. Not sure why that piece is of interest.
If that is a piece of a wall or jamb or infill cmu then I can see a vehicle impact causing damage.
But if that were a structural column it should not have been important to the stability of a 12 story concrete structure and loss of that less than significant capacity should not have caused a collapse.

 

[Nukeman948]

Where does the "vehicle impact" fit on "Maud's timeline Of Doom".
The building was making failing noises for two hours before the collapse.
Did the "vehicle" hit two hours earlier and nobody saw it? Nobody reported it.
No vehicle was ever found crashed into a column.
Can you obliterate a column and still drive away?

 

[AutisticBez]

Vehicle damages M11.1, leading to progressive failure of pool deck, then compromising building columns connected via beams. Find me M11.1 intact.

 

[Nukeman948]

Find me M11.1 intact.
40km/h is fast enough to bottom shear a 12 by 16 column. Fact. I even posted the research data on this.

Find me the damaged "vehicle".

I found your research. Your "facts" leave a lot to be desired.
It used computer simulations for the column and car and said: "A shear fracture occurs at the joint when the speed exceeds 40 km/h for columns with dimensions 400 mm or less"
Shear fracture does not equal displacement.
A different study I found said: "The occurrence of plastic
deformation in the car determines the importance of using of a real car in the
experiments instead of a rigid projectile. For crash tests at high velocities large
plastic deformations in the car are predictable but this is not so obvious for low
velocity impacts".

Link

 

[Jeff Ostroff]

Also if a car hits a column, the weakest point for shearing is likely at the 5 to 6 foot height, not at the height a car would hit it at, the closer to the ground you are, I would think you have more strength to the column from lap joints of rebar coming up from the layers below, like the foundation.

 

[Optical98]

AutsticBez

That column wasn't numbered was it, it was between parking spaces?
Is it behind these?

 

[Vance Wiley]

If I am not turned around, the column would be one bay (+?-) west and one bay north of the corner of the pool - right? The column in your pic just posted with number 40 (or is that 43) painted on its surface?
EDIT - Nope - Sheet S2 shows it as the next column north of one marked 40/43?. I cannot read the number painted there - maybe 38?
EDIT 2 - the pool plaza columns are designated "N" and 12" X 16" with 4 -#7 rebars. One must interpret the note for concrete strength - it could be 3000 psi.

 

[Optical98]

Vance Wiley

42 and 40, 28 is behind 40
I can't see a number on the column behind 42

Yeah, I think we're looking for the column behind 28, and it's under the rubble.

 

[Jeff Ostroff]

Yes in photo find column #40, then look to left is #28 right over the firemen's white helmets, then M11.1 should be to the left of that, but it is under the rubble pile.

 

[SFCharlie]

So it's taken us 29 minutes to realize M11.1 was under the rubble when everything fell toward it during the collapse. What I want to know is how did the slab drop beam fail at M and K, so the whole center façade could fall as one?

SF Charlie
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[Optical98]

What we do know is that all of the surrounding columns to M11 are standing straight up and were not pulled in any direction.

 

[Optical98]

So what if this collapse has nothing to do with Column failure, what direction would you go then? Slab failure?
There were indications that the generator room floor was weak, they intended to reinforce it for new equipment..

 

[Nukeman948]

What we do know is that all of the surrounding columns to M11 are standing straight up and were not pulled in any direction.

Scroll up to the last picture Jeff posted and put an eyeball on M9.1. Does that look plumb to you?

The generator is on the opposite side of the building from where the collapse started and was strong enough for the old equipment that was still in place. There is no evidence of a "vehicle" hitting the generator.

 

[Optical98]

I didn't say anything about a vehicle.. And you should watch some of the videos showing heavy equipment rolling over and grinding into the basin floor right in that area by the pool. They used that area heavily to bring equipment in and bring debris out. So it is no wonder many of the column stumps are bent and ground down.

 

[Nukeman948]

And you should watch some of the videos showing heavy equipment rolling over and grinding into the basin floor right in that area by the pool. They used that area heavily to bring equipment in and bring debris out. So it is no wonder many of the column stumps are bent and ground down.

And this is precisely why nobody should be using the condition of the column stumps or any other objects in these pictures to support any hair-brained theories.

Sorry about the vehicle jab, it was just the main hair-brained theory of the day.

 

[Optical98]

Nukeman

Any investigation will be looking at objects in the pictures.
I try to stay open minded when presented with theories or maybe not even theories but a desire to talk thru an idea objectively. And I always appreciate the same courtesy.

 

[ChiefInspectorJ]

Interesting theory. Where are these items in the pile?

 

[Nukeman948]

Any investigation will be looking at objects in the pictures.

The investigators were there for the entire process and documented every piece of evidence as it was uncovered. That is far different from a snapshot in time with almost no context. Like taking video through the fence weeks after the site is cleared.

I keep an open mind too but there are limits when the flaws in the theories are so obvious.
You want to discuss how it started with the generator? Go for it.