Miami Beach, Champlain Towers South apartment building collapse, Part 09 139

[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

SF Charlie
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[AutisticBez]

Auri, me and the wife were staying at a hotel, and the power went out during the night to just our room. Management were having a big party on the roof and decided to turn off random rooms where the air con was running.

It was pitch black and by morning the room was a modest 35 degrees. (Vietnam). We never considered leaving the room or trying to contact anyone. Who cares? Power is out. Who the hell abandons a condo with windows just because the power is out? Makes little sense to me. But maybe i am just a tight ass.

 

[Demented]

...couple o' things
I think it's Federal Emergency Management Agency?
I think it's the National Institute of Standards and Technology that is doing, (and has been doing for some time,) forensic engineering

Failure Mode and Effects Analysis.
FMEA.

Sorry. I spent a lot of time looking for stress cracks in fasteners and weldments that initiated failure events in the past.

 

[Demented]

Just an idea because I have not a thought as to what that debris would be.

I don't think this is the right location for this to just fall down. If these stairs were fastened the way they should have been, there'd have been some, not a lot, but some, upper support on that roofing slab. If slab tor away at wall and around base, load on stairs and column would massively increase, with a rotational force clockwise.

Probably more likely more deck that sheared and tilted, possibly on a column. This again was an area of extensive concrete repair in the 90's. One of the sections that possibly only had either 305 stainless rods roughed and inserted, or 3 #5's. Hard to tell from the napkin sketch on the permit.

Edit: Yeah, it's just crappy ring camera video, but I really do suggest everyone listening to the video again for at least 30 minutes in a dark room.
Edit 2: Has anyone found or seen the staircase in the debris? Should be at the top of the pile yeah?

t=sqrt(2d/g)

Edit 3: Yeah, I don't know... Earlier large photo had a different angle.

 

[12345abc6ttyui67]

Regarding scooter / car / hotel.

Perhaps it's as simple as they had to pay for parking at the hotel and didn't want to? Simple solution would be to park at home, return on the scooter, and keep the scooter in the hotel room. Next day return home on the scooter, get the car and go back to the hotel to pick up the wife / luggage.

If the hotel was close to home, and the parking charge excessive, I'd certainly be weighing up the pros/cons of this. Granted I'd probably decide my time was worth more than the money saved, but that comes down to personal circumstances.

 

[Demented]

Depending on where they would have gone for a hotel room on a Wednesday/Thursday in the late PM/Early AM hours, a vehicle break-in is more likely than that issue over expensive parking. There's also the possibility of the night clerk either not knowing how to or being unable to produce a parking pass, and parking between hours of 10PM and 5AM is prohibited in certain places along the beaches and Miami area.

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

 

[12345abc6ttyui67]

All good points as well. Just playing devils advocate that there are plenty of rational decision points which might make someone decide that the car / scooter arrangement made sense.

Plenty of people seem to be happy to point out that it seems weird, without knowing anything at all about the people themselves or what they may have been thinking.

 

[Nukeman948]

Better yet, one has to wonder why folks who seem to be against FMEA enter the forensic engineering area.

fo·ren·sic
/fəˈrenzik,fəˈrensik
adjective
adjective: forensic

relating to or denoting the application of scientific methods and techniques to the investigation of crime.
"forensic evidence"
relating to courts of law.

noun
plural noun: forensics; noun: forensic

scientific tests or techniques used in connection with the detection of crime.

Scientific methods should follow the evidence. This building seemed to fall from the bottom up, not the top down.
Should we focus our search for answers on the roof? Nothing dropped from the work being done on the roof should have lead to a partial collapse of this building. There is a very good reason why people like the "Building Integrity guy" haven't mentioned OSHA anchors nor tar kettles. They are irrelevant as far as the failure of this building and have only been discussed to further some misguided theory.

We see many signs of poor maintenance and design deficiencies as well as issues with concrete quality and plan adherence with regard to rebar placement. Perhaps these are areas where we should place our focus and stick to scientific methods instead of the wild conjecture and conspiracy theories that has been seen here.

I find it insulting to think anyone here is "against FMEA".

 

[zebraso]

Earlier large photo had a different angle.

Ah yes. You have shown the triangular tear-out is attached to......column and the wall is the portion I was calling "stained" contiguous with tearout past the column and is planted down in the debris pile. Or the debris is planted around it. Can't tell anything from a single perspective. I knew I was wrong about what it looked like. Nothing to see there. But then you can't tell when that fell in the sequence either. I mean not really. Nothing piled on top of it but that doesn't mean too much because its on the edge of the pile. is there a reaction between it and the slab or did it fall into a hole?

 

[Jedidad]

As for the scooter, according to locals, the cost of hotel parking is very high in that area. So, to save money, he threw their car down in the free garage and scootered back to the hotel.

Ah, that makes sense, thanks. He'd then zip back to the condo in the morning to retrieve their car to bring the wife and luggage home.

 

[Nukeman948]

I still have my doubts about this causing the tearout we see though, but work was likely done drilling in that exact location. Would they have used the same 3/4" anchors?

The columns with the tear outs appear to be the ones that had the concrete beams that held the larger A/C unit. When the original collapse happened these beams pulled out from the top of the columns leaving the shape seen in the demolition video. It seems the lack of rebar at this point may have prevented those beams from pulling down those columns and helped stop the collapse at that point.

 

[sgw1009]

Edit 2: Has anyone found or seen the staircase in the debris? Should be at the top of the pile yeah?

There are at least a few sections of the NE staircase visible.

 

[arbitraria]

Edit 2: Has anyone found or seen the staircase in the debris? Should be at the top of the pile yeah?

Wasn't sure if you meant the northeast stairs as sgw1009 delineated above, or the exterior stair to the machine room? If I'm not mistaken, I believe these are the latter.

That photo was from July 2, but I believe they hadn't removed much from the area due to the proximity of the remaining tower. While I was searching for an older photo, I found one from June 24 at a different angle which I believe shows the same stairs (red arrows). Forgive me if this particular point has been addressed previously, but I do recall mention of tie-downs with the roof work and AC units. I hadn't noticed what appears to be a yellow ratchet strap tied off to one of those red AC platform beams, said beam kinked at that point. The other end appears to be attached to one of the new roof anchors, possibly? That kind of deformation, to me, shows the anchor put up a pretty good fight as the building tore apart, and it eventually popped out of where it was attached. (To be clear, I'm in the "accumulated pile of exacerbating factors leading to eventual failure" camp. I just found this interesting as there's been so much discussion of this area of the roof.)

 

[MarkBoB2]

253RWD, thank you for the photo showing the door to the middle roof above. Fortunately, I had agreed earlier with Santosi81 and Murph_9000 that a door was there.

Now, if you look closely at the photo you may see something interesting that you, Murph_9000, and Demented (who also posted the same photo above), may have missed. In the photo underneath the stairs you can see three air conditioning units that are not tied down to foot-high metal supports like they should be. And they appear in a place where air conditioners are not shown on the architect's drawings. Clearly, these air conditioners are either old ones being replaced or new ones to be installed. If unsecured air conditioners can be found on this part of the roof, then it is likely that others also can be found on the penthouse roof adjacent to this area, from where one or more of them could have fallen down to the deck below.

Question. Do you know when this photo was taken?

 

[Nukeman948]

I hadn't noticed what appears to be a yellow ratchet strap tied off to one of those red AC platform beams, said beam kinked at that point. The other end appears to be attached to one of the new roof anchors, possibly?

I'm not too sure a ratchet strap would be strong enough to kink that beam but a lifting sling would be. I can't find a spot on the still standing portion of the building where the other end may have been attached so it could have been attached somewhere on the part that collapsed.

Edit: It also looks like the beam twisted nearly 90 degrees if that helps anyone.

 

[sgw1009]

I can't find a spot on the still standing portion of the building where the other end may have been attached so it could have been attached somewhere on the part that collapsed.

Looking at the roof view from 2021 (with the new unit on it), the eastern (right) two beams are painted red, while the two beams under the HVAC unit are not visible. So the crimpled beam would have to be the eastern-most beam of that assembly. This is away from the standing portion and towards the portion of the building that collapsed. Looking at the roof view from 2021, the crimping would have occurred on the right-most (east-most) beam, about 1/3 of the way up from the bottom (from south to north). This is essentially the center of the roof, so no obvious need for an anchor point at that location. No ideas on what that was about.

 

[Nukeman948]

Looking at the roof view from 2021 (with the new unit on it), the eastern (right) two beams are painted red, while the two beams under the HVAC unit are not visible. So the crimpled beam would have to be the eastern-most beam of that assembly. This is away from the standing portion and towards the portion of the building that collapsed. Looking at the roof view from 2021, the crimping would have occurred on the right-most (east-most) beam, about 1/3 of the way up from the bottom (from south to north). This is essentially the center of the roof, so no obvious need for an anchor point at that location. No ideas on what that was about.

I agree with all of that. Among the things we don't know is why was the sling there? Did the red iron fall first and rip out the anchor, or did the point it was attached fall first and pull down the red iron? It almost looks like the iron was bent upwards but it my have bent when it hit the debris pile.

 

[Reverse_Bias]

Arguments against the roof being a trigger.

One of those AC units weighs 200lbs, there's a parapet wall, and the roof has almost no slope. An AC is not just going to fall off the roof cause it's not tied down and there's vibration or 20mph winds. You'd have to put the thing on wheels and take away the wall to make this scenario plausible.

If the roof did collapse first, everyone who saw it is dead and nobody reported it to 911.

So the theory is relying on some mystery force, or a sneaky roof collapse that killed everyone who saw it like The Ring.

I'm not ruling it out entirely, just saying the odds are very slim.

 

[sgw1009]

So one would think that the larger beam would be under the four smaller beams, giving them support. But looking at the photo below, it shows that the opposite is true: the larger beam is on top of the four smaller beams. So this means that we are seeing the bottom view of the assembly (colors of which are unknown), with the crimped beam still being farthest from the standing section of building. Note that this is the old HVAC unit, and the new unit was installed to its right. But the support assembly is the same.

 

[Nukeman948]

So whatever was tied to the beam was to the west of the HVAC assembly, not the east.

And if we're not confused enough already, did the strap go to the east, or maybe under the unit to the west? Were they using it as fixed point to test the new roof anchors? Maybe it went over the unit to hold it down because they were changing the method of securing it to the steel? Good questions often lead us to more questions.

 

[tmwaits1]

Agreed that it seems very unlikely that the AC units were at all involved in initiating the collapse, but there is some confusion when people talk about the “roof first” theory. The AC units aren’t the only thing that could have fallen off of the roof. The original plans show the roof parapet to be CMU block with Reinf. Concrete columns at 20 ft supported on the roof slab which is cantilevered beyond the building. This system has a number of weaknesses so one can imagine several plausible scenarios where a 10 ft long section of this parapet wall could have fallen off the roof and crashed through the plaza deck. In fact you could probably argue that this is more likely to have occurred than a spontaneous collapse of the plaza even granting that the plaza was poorly designed and maintained. The question of why the building collapsed instead of a more localized failure I think will come down to a plethora of errors in the original design.