Miami Beach, Champlain Towers South apartment building collapse, Part 05 111

[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


SF Charlie
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[Murph 9000]

Maybe these white rocks are bits of the missing column? Again though, it seems crazy how far they are from where the column was.. this is about a car length and a half away.

They could possibly be from the top of M9.1, the result of severe damage to it when the pool deck and heavy stepped patio beam dropped. The east / right hand side of apartment 711 dropping slightly ahead of full collapse fits with that column failing in the final moments, then spreading out under the building from there.

 

[AutisticBez]

Murph 9000,

The missing column from the Tiktok video is really a problem. Nobody has been able to explain it. All the columns under the pool deck, do a punching shear. You can find all of them but the one at the bottom of the ramp. Maybe it's obscured by debris? Maybe it was destroyed by the building collapse? It's just not present. Is it possible for falling debris from the roof to cause it to collapse on it's side? Then again, without the TikTok video, there wouldn't be vision of the missing column.

I know of one person who's backed a car into a column at 20km/h, it was a massive bump even at that low speed. I think people think these columns are super strong. They hold a pool deck up, how strong do they have to be? They might be very strong, but the connections to them aren't going to be that strong at all. Shear at the bottom is what I am thinking. Research itself points to this, with clear lab testing.

 

[GPR_Tech]

.
Frequency illusion, also known as the Baader–Meinhof phenomenon, is a cognitive bias in which, after noticing something for the first time, there is a tendency to notice it more often, leading someone to believe that it has a high frequency. (a form of selection bias)

Engineers understand this and they have a engineering method to evaluate problems systematically.
Other disasters also point us to this process taking many Months to Years... before they will have the likely answers to what was the cause & contributing factors for this.
Until then, this is a good forum to discuss many theories...

 

[Demented]

To all of those saying a car hit the column, are you saying it came down the entrance ramp? Did it come from the west underground side of the building?
In which position could the car have come from, with enough speed to obliterate that column and leave it laying towards the west in any way in the way everyone is claiming to see the column?
There's a good chance that column may still be partially, if not fully intact in that video, we just can't see it hidden behind planters, deck furniture, water draining, paver and concrete rubble, and dangling waterproofing membrane.

I'm still saying it looks like water found it's way down a weak point after collecting on top of the membrane. You don't even need a full section to fail, just enough to begin the destruction, that could from the top, match what was described as a sink hole opening up. A slow failure of debris getting swallowed up from the pool deck that spread to the collapse we saw. The TikTok video gives us at most 5 minutes of zoomed in compressed and grainy 380p. You guys are seeing far more detail than is actually there on shitty stills.

This was the section with massive water intrusion issues leading to water pooling on top of the membrane, correct? Not saying the column didn't collapse in anyway, but there's far more likely and explainable reasons as to why, considering the area, the deterioration, and the known issues. It's been very rainy down here. I mean, are we really trying to push aside known damage to an area from years earlier that has yet to be repaired?

Precision guess work based on information provided by those of questionable knowledge
Aerospace/Industrial/Medical/Structural
SoFla

 

[julootamu]

waross posted a picture of a Rheem tie down strap for a split system AC unit. Looks almost home made. Here are pictures of hold downs on AC units installed at my house:

1. Picture of one of four bolts holding down a 3.5 ton Carrier (Factory provided holes but the top grill has to be removed to install). Replaced the Carrier w Mitsubishi.

2. Mitsubish Mr Slim heat pump with factory tabs (two on each side) to hold down AC unit. Prior to installing nuts on threaded rod embedded in concrete blocks that elevate the unit above the original slab. Blocks also anchored by rod into original slab.

 

[John2025]

I have a 2 ton and a 3 ton a/c on the concrete roof of my single family home in a hurricane zone. I have no doubt they would've blown over on the first windy day without being bolted down, but chances are the tubing and wiring would have kept them from going far. Plus they weigh maybe 100-150 lbs. Does anybody really think something of that weight could cause a collapse? Would a human body falling from the roof cause a collapse?

 

[julootamu]

No I don't think a 100-200 lb AC unit falling off the roof in any way should have caused a collapse like what happened. Building supports should have been seperate ftom pool deck columns. Just like when I designed a deck behind a house. Made it free standing and not attached directly to the house.

Surprised that another camera didn't capture in higher resolution the collapse. Hope they find one to dispell roof debris idea easily.

I just posted due to one poster saying AC units are top heavy (they're not and fan motor typ. only weighing 20 lbs with heavier compressor at bottom of unit)) and other posters saying AC units aren't bolted down. Absolutely should be in huricane areas and AC manufacturers have provided mounting holes forever. All units I've been involved with have been bolted down and I'm inland. Commercial building codes require it and I'm sure residential codes in many areas. Just good practice at least to deter copper thieves.

 

[gonefishing2]

Ok, if first pot hole was in patio slab minutes before building collapse, then the planter area is a prime suspect for punch shear failure of slab, leaving beams initially in place. Planter area outside 111 has not one but 3 beams tieing columns together under planters outside of building footprint. The 4th beam that closes this square area is at building perimeter. Thus more likely a bundle of rolls of tar impregnated heavy roll roofing felt/paper is able to take out slab before the 3 beams under planters. Roof first, patio slab pot hole second, then planter beams next, and so on.

Sorry 4th beam at slab step down.

 

[Spartan5]

If I heard the Penthouse roof crash down and got woke up in middle of night, the last thing I would do is call 911.

I would get my ASS moving fast

If the roof collapsed several minutes before the rest of the building, more people from the upper floors would have been woken up (and escaped) as a result. There’s been no indication that that was the case.

 

[gonefishing2]

Spartan5, please keep firing to poke holes in the roof first theory that some folks believe may be near top of possibilities. It is our back and forth that roots out the weak theories. And we still don’t have anything to proof who has nailed it and who is left wanting.

 

[microwizard]

The main problem with the "roof first" theory is that there is no evidence for it. At some point you have to apply Occam's razor, rather than keep adding caveats like "maybe all the people in the top floors happened to be heavy sleepers". Also there were lights on in the upper floors, so it is likely people were awake anyway.

 

[gonefishing2]

i see the penthouse roof missing, already collapsed in the security camera video. So I have visual evidence from two grainy pictures. Those videos are the best evidence we have to date in public domain.

 

[microwizard]

i see the penthouse roof missing, already collapsed in the security camera video. So I have visual evidence from two grainy pictures.

No, analysis shows the whole section has shifted down by the time the video starts. The penthouse level has not collapsed.

 

[gonefishing2]

The 4th piece is the weak slab to column connections we have seen where we had punch shear of slab.

 

[Seppe]

i see the penthouse roof missing, already collapsed in the security camera video. So I have visual evidence from two grainy pictures. Those videos are the best evidence we have to date in public domain.

So you are certain that the first available frame of that video isn't just showing the central stack of the structure already in a state of collapse to the tune of about two stories worth of "fall"?

Even with all of the color-coded line overlays, text boxes, and dot-connecting from previous user posts, my eyes aren't drawn to the "roof is the trigger" conclusion. I personally think that there are more plausible (and boring) plaza-level initiating factors than there are roof-level triggers. But it's interesting to see people's different theories.

 

[Spartan5]

Spartan5, please keep firing to poke holes in the roof first theory that some folks believe may be near top of possibilities. It is our back and forth that roots out the weak theories. And we still don’t have anything to proof who has nailed it and who is left wanting.

Thermopile… it’s tedious. I’m more of an Occam’s Razor kind of guy.

I mean these residential AC units for instance that “rolled” through a parapet wall and/or plummeted into a concrete slab at 70 MPH but are still perfectly recognizable in the basement on top of the slab they punched through??

To me it’s somewhat of a waste of effort. I see of lot of ideas that are having “evidence” manufactured to support it. And I’m most concerned about how any of this could have happened under the care/watch of a structural engineering firm that was being paid over a half a million dollars for their services to ensure that the building is safe and structurally sound.

Barring something new/concrete coming out, for the time being I’m content on chalking this up to the planters. Or maybe a vehicle in the garage. Otherwise we are straying into “disgruntled resident with homemade shaped-charges” territory.

This is usually a place that I hope to find my daily dose of rationality.

 

[bones206]

The main reason that I keep an open mind about a roof level failure is the timing. Coincidentally there was work done on the roof within 24 hours of the collapse. Any good investigator would chase down that angle even though it may just be a pure coincidence. Other than the timing aspect, there’s not much evidence at all indicating a roof level trigger event. Just a lot of circumstantial tidbits that are worth noting, but nowhere near being smoking gun evidence.

Since we are all taking turns squinting at the time tok video stills, here’s what I see: planters tilted on their side, with foliage facing the camera (outlined in blue). Planters resting on the plaza slab which has cracked in half. The exposed cracked edge of the slab is facing the camera (outlined in green and hatched) and the darker area below is the bottom of the slab. We see the top of the plaza slab in the foreground (broken edge outlined in green). Red outlines may be remnants of column M11.1 and possibly part of the beam, but I’m less sure about that.

 

[gonefishing2]

Spartan5, I read that our PE SI, Morabito is managing the core sampling subcontractor (possibly his son's company), and requiring X-Ray of Slab before core sampling to ensure there is no damaged rebar. Yet, Morabito's pictures show clearing they could not have centered better over a rebar before drilling cores, than they did.

So I am glad someone has confidence in the PE SI Wizard....

 

[Seppe]

I mean these residential AC units for instance that “rolled” through a parapet wall and/or plummeted into a concrete slab at 70 MPH but are still perfectly recognizable in the basement on top of the slab they punched through??

Nothing stops a Trane.

 

[Demented]

The main reason that I keep an open mind about a roof level failure is the timing. Coincidentally there was work done on the roof within 24 hours of the collapse. Any good investigator would chase down that angle even though it may just be a pure coincidence. Other than the timing aspect, there’s not much evidence at all indicating a roof level trigger event. Just a lot of circumstantial tidbits that are worth noting, but nowhere near being smoking gun evidence.

Since we are all taking turns squinting at the time tok video stills, here’s what I see: planters tilted on their side, with foliage facing the camera (outlined in blue). Planters resting on the plaza slab which has cracked in half. The exposed cracked edge of the slab is facing the camera (outlined in green and hatched) and the darker area below is the bottom of the slab. We see the top of the plaza slab in the foreground (broken edge outlined in green). Red outlines may be remnants of column M11.1 and possibly part of the beam, but I’m less sure about that.

That's pretty much what I see as well.

If the roof went first on the penthouse, there definitely would have been a fire alarm trigger of some sorts. We don't hear that in any of the calls, videos, or survivor testimony.
If the building is already collapsing in the start of the security video, as we know it already is, wouldn't that put the roof of the penthouse at roughly the same angle as it would be had the roof just collapsed first?

Also, is this argument of the roof first also saying that what ever did fall, managed to make it over the roof wall, stay in a fully recognizable shape, and fall in nearly the identical spot it would have been had it been on the roof, all while punching through the slab?

Precision guess work based on information provided by those of questionable knowledge
Aerospace/Industrial/Medical/Structural
SoFla