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
Eng-Tips.com Forum Policies

 

[Vance Wiley]

Can't let that go without comment - mostly in jest, of course.
So why is it that if some A/C system fails miserably and some occupants get hot and a bit sweaty it does not immediately draw an 8 segment forum response with as many SEs chiming in as there are M and Es here?
Maybe the SEs work in a more risky and exciting profession? From a risk/reward view, it is not too smart, I will quickly agree.
But for the moment this SE discounts the influence of a failing 600 pound roof mounted condensing unit - no matter what head pressure it developed or voltage it operated at or even if the half horse cooling fan became unbalanced and vibrated the anchorage loose.
With that said, Dave, I would like to buy you a drink should we ever meet.
I do appreciate being warm in winter and cool in summer, thanks to Mechanical Engineers.

 

[Demented]

@Nukeman
I have respect for others work, just no respect for shoddy work. Hard concept to grab, but there was a lot of "good enough" done on this building to be as cheap as possible. I used to joke a lot at work about stuff being good enough you could throw it off the roof and it'd survive. Yeah, you know what, a co-worker's rails actually fucking survived that fall. I gave him props.

Maybe I worked with these guys in the past.
If anyone in SoFla knows a loud mouth drunken POS drunk who wears penny loafers to job sites while screaming about tits and ass, you know this isn't the only cooling tower. The aluminum ones this dude did on that Target have glued on bolt heads.

The work on the W side, as well as the permitting and plans there, hell of a lot different than the ocean side. The town only seemed concerned with turtle lights on the beach side, but making the street side beautiful and correct.
Sorry, but even the welds were not done to the new engineers callouts. Clear as day in the photos from Morabito. So yeah, I'm gunna knock what would have been a fail if a CWI would have inspected the weldment. If we start allowing bullshit to slide, we're going to start seeing more issues with structures. When are people going to have the balls to stand up, put their fist down, and demand it be done right?

And yeah, you're right, you could power a bank of tig machines up there. These days inverter machines are so nice I can get 200A at my torch out of a 115v wall socket. You're not dragging a tig up there though for that job. There was also no crane, so that's a no on hoisting the Trailblazer. You're not dragging leads 12 stories up either and expexting to be able to weld. A small AC/DC 220v transformer power soure was carried up.
I got my first Dynasty 200DX around this time they came out. Aint no way I'm dragging that to a roof in the FL rain reason.
BTW, where in any of their plans for the beam replacement did it call for supporting the upper beam that was being supported by the steel beam, with a lower beam on top that was resting on the slab? I haven't found that in any drawing, permit, nothing so far.


There seems to be 2 crews that did a few jobs on this site, and did it very poorly. Even reading the entirety of the filed reports and inspections, the work was knowing done incorrect, but passed off by the FI, SI, and town building inspector. And this was concrete restoration work on the roof, columns, balcony, interior slabs, AND POOL DECK. Hell, even if the pool deck did fail first, and the building really did just crumble and fall, which is a possibility that I am fucking terrified of, so what if I'm chasing crazy, ignore it, focus on the very damning evidence of shoddy work that was done to the support structure of this building by these crews. Poor maintenance indeed, but not by the condo board as I've seen suggested by a few.
I'll keep chasing my tail in lala land until my FOIA on the images from the above mentioned work is handed over. Sadly at this point I think those pictures may be gone.


@Santos81
Blurrier than the TiKTok video, lol. Yeah I guess that's what it is. I suspect you've seen the full videos as I think you've hinted at in the past so no reason to doubt what you've seen. Scratching that off the list.

Have newer models begun to take into account the rebar replacement, or lack of, as well as delaminated sections of full or half depth slab replacements?
BTW you still got those flow surveys? Was interested in seeing that.


@Waross
Until then, I had never seen spots like that, and as you can recall, I highly suspected they were NOT patches. We don't see those patterns on the tops of slabs or the side of walls in pre-cast structure from the foundry's that have been involved, so sorry I've never seen them before. For the last 15 years or so all I've seen if OSB for wood forms. I do my best to avoid wood and have no shame in admitting I know not a damn thing about it. I even asked our wood shop guy, and he's never seen that, and he's been working with wood since before Jesus; round, oval, and the occasional square is all he's ever seen until I showed him that. Learn something new every day.

Also no, this was a varied age condo. The Avg age likely being somewhere in the 40's.

@Spalso,
To add to that, could we let out of state construction firms build everything too?
I've done 3 month stints at timeswith a certain Texas company who's been doing a lot of work in the below Orlando area for the last dozen or so years. It is a whole other world of proper that I just don't see with Florida based companies.

@Nessman
Planter drains were upgraded and waterproofing was replaced. Maintenance was done. Crews just neglected to do the job correctly as can be seen from the odd layering in places.

@MaudSTL
The FCP had a silence feature for certain alarms to be programmed in during certain hours. I need to read the manual for it again but I believe you could even program the system to only flash the fire lights but not trigger the buzzer even in the event a fire handle (jefferson alarm) were pulled. There's no indication that this was ever programmed to be silenced, but another possibility in the "why were there no alarms" until after.

 

[arbitraria]

So, were the residents of the -11 units the only ones who received any warning?

Adding to MaudSTL and Optical98's responses - I don't think they were there only ones, but it is possible that the sounds, sensations, and visual cues experienced in the x11 stack were the most alarming, and happened just early enough in the collapse that those handful of people had time for their flight instinct to kick in. (Obviously 111 had a good chunk of time they observed peculiar noises, but it wasn't until the collapse was visibly in progress and very apparent that the severity and panic prompted quick escape.)

We don't know if the woman in 410 heard or felt something that caused her to go out onto her balcony, or if she was already out there and through sheer coincidence happened to see the pool deck cave in. Same for the people on their balconies on the northern side of the building - were they just hanging out, or did they come out to investigate noises or sensations? Was it one unit's residents, or multiple units? I'm not sure if TikTok lady knows that answer, or which units they came out of, but she did try to convince those people she saw to evacuate.

I suspect that investigators have unreleased video from various sides/angles that shows exactly how many residents had some kind of advanced warning, and given the number of people who made it out vs. those who didn't, there was likely variation in how strong and/or easy to interpret those signs were. Add in the variables of disorientation in someone woken from sleep, and the number of units that were unoccupied at the time (thankfully there were many) and it's hard to be able to discern a pattern.

The part of me that still has some remaining un-jaded soul is haunted by the security camera video from 711, I can't begin to imagine how surreal and utterly horrifying it must have been to experience that first-hand.

 

[MaudSTL]

Unit 904, Mother and daughter of Gonzalez family. They heard something and ran out their front door into the hall, took 5 steps and 9th flr fell to 8th..

@Demented has mentioned this several times too. I’ll add the link to the spreadsheet over the weekend. Thanks.

 

[Auri]

remained standing for 7 to 15 minutes. That was plenty of time for evacuation which never happened (lack of emergency planning).

There was lack of emergency notice. We know the silent alarm was triggered by 1:16:39 am courtesy of the 911 alarm company call. The building didn't collapse until ~1:22:20 am. Usually those alarm systems progress to full alarm within 3 minutes. It's possible someone silenced it seeing as it was just a plaza collapse - and sadly they're innocent! It takes an engineer, or thoughtful physicist, or specific training to realize how much a ground level collapse threatens the tall building nearby.

This might happen again if we don't independently brace building boundaries next to collapsible space, or else train everyone to evacuate a building if something nearby sinks through. It might not be a degraded plaza next time ... could be a rogue truck, a battery fire, a terrorist...

For all these buildings being (re)-inspected, allow only people from out-of-state, with NO business ties to Florida, to do the inspections.

During the Texas power outage the complaint was that someone from out of state sat on the commission and thus had no vested interest in preparedness. If there's a weakness specific to the industry in Florida we ought to address it directly. I have a hard time believing state residents don't have motivation to make communal structures safe & habitable. Consider that their building laws could be too tough in practice, meaning inspectors get overwhelmed and sloppy. Maybe it's condo laws. Or maybe they could use expertise from out-of-state, even foreign. The bottom line is still collapsed structures/safe failure modes.

 

[Murph 9000]

Not surprising. If the building had major structural issues it would have failed a long time ago. People gotta remember - something like this isn't caused by a single event but a series of events in the days/hours/minutes leading up to the collapse, caused by prolonged deferred / neglected / poorly executed maintenance over a period of many years since the building was first constructed.

Reinforced concrete can last a surprisingly long time with major structural issues. The Hotel New World in Singapore was built in 1971. The engineer forgot to include the dead load (the massive weight of the building itself), calculating only for live load (people, furniture, equipment, etc), resulting in RC columns which had nothing like the required capacity for the building. Over the years, they added large HVAC on the roof and a bank vault on the ground floor. The building kept complaining, it gave clear warning signs, but it did not collapse immediately on any of these significant additions.

It eventually collapsed in 1986, apparently without a triggering event (i.e. no obvious straw breaking the camel's back). One of the columns, which had been cracking for years finally gave up the struggle, everything else was already massively overloaded and cracked, and the entire structure basically just dropped.

That was a massively overloaded RC structure from before they even finished building it, and it took 15 years to collapse. It's conceivable that some major structural issues can take 40 years. That's not to deny the influence of bad maintenance, only to highlight that major structural issues can lurk for decades; until either normal slow degradation, improper maintenance, or some other combination of aging / damage / abuse factors finally lead to failure.

 

[LionelHutz]

Right, All I think it proves, is that I was right several threads back, to say that a video from a smartphone, whatever, of a security system display, that's out of focus, (and compressed in the phone and again in YouTube) is practically immune to analysis.

Yes. I was able to look at it easier to confirm, but I saw the same thing as I did the first time I viewed it. Crappy detail that makes it very hard to tell, but it still appeared the collapsing floors had dropped a level by the time the video started and the roof was still there.

This is why each frame must be registered The smartphone, whatever was moving around quite a bit.

You did a really good job lining them up, but from frame 26 to 27 the right side appeared to drop a bit while the collapsing area appeared to go up a bit. Just shows how crappy the video is.

The 13th floor should be present over the double pillar, and the right side, but not over the left side (there was no floor 13 there). I'm struggling to see in your version what the visible structure on the left side on that floor is.

I didn't comment on this, but to me it appears to be un-collapsed building behind the falling facade. Nothing about the appearance there makes me re-think the levels. I see the 12 floor balcony and the 2 levels of parapet that have all dropped about 3 floors in the 25-27 frame range in the powerpoint, and there is building visible above that too.

 

[SFCharlie]

but from frame 26 to 27 the right side appeared to drop a bit while the collapsing area appeared to go up a bit.

Thanks for the feedback. Unfortunately, PowerPoint only allows for rotation correction in one degree increments. I've gone back and captured the twitter video. I've dumped out about 200 frames. I'm not going to crop them. I've figured a better way to stabilize the brightness and contrast. I'm still thinking thru a better way to register them, but I'm not sure it's worth the trouble. The jerky movement (which can be seen in another's slow-mo) is not uniform as far as I can tell. Sometimes there are three frames in a row with movement and sometime 5 or so without. The pattern is not totally random, but not consistent like a beat frequency. I don't know?
Anyway Thank!

SF Charlie
Eng-Tips.com Forum Policies

 

[Optical98]

arbitraria

"I don't think they were there only ones" to receive/hear a warning.

Roberto Castillero and Adriana Sarmiento who were staying at the Bluegreen hotel next door across 88th - she took the video of the garage etc.

In his interviews he says there were people out on their balconies (some had come out having heard a "boom") and she was waving n yelling for them to get out, but evidently they didn't understand her. He speaks of actually watching a man fall once the collapse started and they (this couple) had to run to escape the debris.

Waross

"Was this a retirement condo?"

No, although there were many elderly living there, many of the Units were rented out and some were used as Airbnbs. That is why many young children died.
Of the collapsed condos (77), my rough count is that 26 of those units were occupied by retirees. 34 Units were empty.

Survivors from the West side do mention a fire alarm, but seems like it went off after the collapse.

But a good question to ask is how are the elderly expected to escape a fire or emergency if elevators are programed to stop and many can't walk down stairs?
Or say handicapped people in wheelchairs??

If their neighbors don't happen by to carry them down (which we know happened on the West side), the rest have to go out to their balconies and hope the fire trucks get there in time?

 

[spsalso]

If the building had major structural issues it would have failed a long time ago.

I guess that just shows that the developer was a visionary.

Why waste money on putting un-needed rebar in when the building will last until maintenance failure brings it down?

spsalso

 

[Nukeman948]

Survivors from the West side do mention a fire alarm, but seems like it went off after the collapse.

I don't know if the fire alarm system is the original one from 1980, but for the original one, a manual pull station, smoke detector, or sprinkler flow switch will transmit a tone alarm for that floor only. After a time delay of 0-10 minutes, if not reset, a general alarm will alert all floors.

Elevators will return to the first floor so passengers can escape and are not sent to the floors that may be on fire. Security personnel and fire personnel have keys to operate the elevator after an alarm for a controlled safe evacuation.

 

[Js5180]

I have looked through SF Charlie’s frames and I see an issue in the basement-first theory. Not enough to rule it out entirely, but something that doesn’t seem to have been addressed much.

In Frames 24-34, the white band on the exterior of the K10/K9.1 column appears not only intact but nearly unchanged IN HEIGHT. The floors above it have collapsed across the entire x10-x11 units, but the K stucco band has barely dropped, if at all.

That’s not to say a collapse of the L and/or M stacks could not have originated in the basement. Clearly, there’s a lot more movement around L and M, and of course that’s where the rubble was seen.

But the white K column stucco band simply did not drop 40 feet, while everything above it did.

And interestingly, if the two flashes are indeed the result of the conduits being cut in the corridor ceilings of 9 and 11, and the upper floors over the x10 units were collapsing while the lower ones were not (yet), that would also explain why we don’t see any flashes on floors 7, 5, or 3.

 

[Optical98]

Nukeman,

I'm not sure either, if it was the original. I think I saw plans for updating parts of the system, maybe just the sprinkler system.

In one of the very early videos, prob a tiktok... you can hear it.

Regarding the elevators... there is no mention of the security guard doing anything with them, I think they were broken or not working as survivors said the doors were open and shaft was empty.

 

[arbitraria]

But a good question to ask is how are the elderly expected to escape a fire or emergency if elevators are programed to stop and many can't walk down stairs?
Or say handicapped people in wheelchairs??

The egress requirements typically address fire and smoke emergencies - someone in an area with frequent seismic activity may have better information with regard to egress from collapse situations. Those with impaired mobility would be expected to wait for emergency crews to rescue them if an elevator is not available. Code would generally require an area of refuge attached to a fire stair that would function as a safe place to wait for said rescue; this requirement is waived if the structure has an automatic sprinkler system.

 

[Murph 9000]

I don't know if it was officially designed / designated as a fire refuge, but CTS had a small open balcony between two fire doors on every floor, as the access to the west stairwell. It could have certainly have served that purpose, being both protected from fire and open air.

The important thing with elevators automatically going into fire service mode is that it disables the hall call stations (so the fire can't call the elevator to the fire floor). It also changes the doors to a special fire mode where they don't open and close automatically and allows a peek function to briefly open them an inch or two and confirm fire and smoke conditions before fully opening them. In essence, it puts the cars into an attendant service mode, and the initial automatic recall to the lobby allows security or firefighters to verify there's nobody trapped in an elevator.

 

[Nukeman948]

All good info on how building systems deal with emergencies. Some systems I have installed also had fans on the roof that blew fresh air into the stairwells so people evacuating didn't die of smoke inhalation. Yes, air will feed a fire but the thought is it's more important to save lives than property, and people die from lack of air but the fire doesn't.

Newer systems have addressable initiating devices to pinpoint the fire location and other features is why I questioned if this was the original system. Programing how it alerts people, shuts down AHUs, and elevator recalls hasn't much.

Another reason for the elevator to return to the ground level is so the firemen know where to find it and don't have to wait for it.

 

[rodface]

For those looking for grassy knolls in blurry videos...

This is how the building would have looked from the camera's precise perspective, when intact.

 

[Jedidad]

But a good question to ask is how are the elderly expected to escape a fire or emergency if elevators are programed to stop and many can't walk down stairs?
Or say handicapped people in wheelchairs??

The elderly and/or handicapped need to consider these things before buying a unit in a tall building. But people don't. They want that nice long range view.

Elevators will return to the first floor so passengers can escape and are not sent to the floors that may be on fire.

But what if it's the first floor that's on fire?

 

[Nukeman948]

But what if it's the first floor that's on fire?

We programed elevators at one hospital I worked on to have an alternative floor as two floors had ground level exits. It is easier to program for different scenarios than it is to convince the money people that it's a good idea.

 

[SFCharlie]

For those looking for grassy knolls in blurry videos...
This is how the building would have looked from the camera's precise perspective, when intact.

...something's not right about the balconies with concrete (is this what we are calling parapets?) instead of wrought iron railings...See above at:

I'm trying to corollate what I see in the video with the real building, so I took a couple of snaps in Google Earth Street View