Miami Beach, Champlain Towers South apartment building collapse, Part 06 131

[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

SF Charlie
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[apper.42]

Just a thought on the debris reigning down in the ring video. Once the distortion of the slabs becomes evident the glass in the sliding balcony door would break allowing outside air to start moving around the apartment/room affecting the direction of concrete chips from the failing concrete. Top bars in the ceiling could be unzipping in tension in a fashion similar to other slab failures we have seen in the debris as the hinge forms.

 

[Sym P. le]

Cutting slab around punchout column approx. 2:30 p.m. edt before storm break. I wonder if they will try to lift the whole section intact?

live Youtube link

 

[Js5180]

Looking at a few possible camera specs, a 110 degree FOV appears to be the best fit, putting the camera about 36” from the left wall and 88” from the window. The room is 18x26, the kitchen is 10x16, the outside corner on the left wall is 18’ from the window wall, and the pillar on the right is about 21’ from the window wall.

 

[Softee]

Video of affected area post-cleanup at 0:49

https://youtu.be/jI6Up5Nv70c

 

[Js5180]

Also, in my opinion, the groaning noise at the end of the video isn’t the building collapsing but rather the table sliding across the floor.

 

[Sym P. le]

The initial collapsed building portion has been cleared to the garage slab. Entrance ramp visible on left and elevator shaft to right. (from Softee's link)

 

[bones206]

These look like the 4 #7 dowel bars for column L11.1 and M11.1. Not sure what if anything can be gleaned from that since we don't know what it looked like earlier in the debris removal process.

 

[Softee]

Earlier in the process at 1:30

https://youtu.be/fyCxzN1xpzU

 

[olynyk]

For those who have not seen it, I wanted to bump this link to the full reserve study which was uploaded in the part 04 thread:

boo1 (Mechanical)10 Jul 21 12:53
Document with work to be preformed. Where is the major structural work?

https://files.engineering.com/getfile.aspx?folder=...

There are photographs of every conceivable major component, the original generator, the security system monitor (could help identify what sort of system was in use).

Page 90 shows the security system views. If the recordings can be saved, there will be a lot of information in there.

 

[Sym P. le]

Back to the punch out slab removal, they've cut it in half. It looks like they also may take the other half. Scratch that, they packed up and went home.

 

[waross]

What are you talking about? I have never heard of Nola Devices.

Nola Technology is a valid technology for very very few applications.
If a 100 HP motor is driving a 100 HP load, there will be no advantage to a Nola Device.
If a 100 HP motor is driving a 10 HP load, there will be an advantage to a Nola Device.
It is almost always better and cheaper to use the correct size motor.
Where will a Nola device provide savings? A escalator in a subway station may be the best example. It runs 24/7 mostly at light load, but during train times at rush hour, it is working at full rated power.
A Nola Device will save energy when the escalator is running lightly loaded.
So what is the problem? Marketing. Almost all marketing for Nola Devices is a scam. Nola devices are touted as cost saving devices and sold for applications where the motor in question is working at or near full load and will not benefit from Nola Technology.
If you care (and I don't blame you if you don't care) look at this thread.
[link thread238-484643][/url]
A quote from one of the leading electrical Gurus.

jraef (Electrical)
29 Jun 21 18:06
I'm not going to sugar coat it. These things are scams.
Quote (Short article)
The concept is that if you can reduce the voltage supplied, then there will be reduction in your electricity bill.
Their opening statement right there is absolute unadulterated bovine excrement. Everything they say after that is their pathetic attempt to justify that initial stupid statement, so regardless if any sprinkling of truisms in there, the entire premise is false from the outset and designed only to extract money from your budget.

What happens a lot, and why they can get "testimonials" (assuming SOME of them are true) is that people approve spending money on these scams, then have to "justify" that by showing savings. But of course what's really happening is that because they NEED to show that, they ALSO implement other simple common sense actions, like turning things off when not in use, raising thermostat settings in summer or lowering them in winter, cutting back on everything, which cuts back on energy use, etc. Then at the end of the year they compare the energy bills and immediately attribute it to these scam devices that they foolishly invested in.

I should know, I used to sell one and was involved in what turned out to be a scam. In my defense, I NEVER told the guy that it was going to save him energy to use them, I was selling him Soft Starters for his cooling fans and they had the Nola circuit on them. But HE (plant maintenance mgr) was chasing a big bonus from his employer for "saving energy", so he submitted the energy bill savings and claimed it was because of the Nola Energy Saver in the Soft Starters that he bought from me. That was BS, the soft starters had bypass contactors so that Nola circuit never was engaged. They saved energy because they ran the fans less. It turned out that people left them running a lot more than necessary because of the old wives' tale that "It takes more energy to restart a fan than it does to leave it running for hours longer". That has NEVER been true, but the myth exists to this day. So when he put in the Soft Starters, he told the operators that it was now OK to turn the fans off when not in use, and THAT saved the energy. But he got his $60,000 bonus and retired. A year later I was called to the carpet because an audit was not showing any real change in the OPERATING energy of any individual motor when running with the Nola circuit engaged (compared to being in Bypass). Zero difference, because the fans were always fully LOADED when they were running.

Nola Devices are named after Frank Nola and are not related to New Orleans, Louisiana.

Bill
--------------------
Ohm's law
Not just a good idea;
It's the LAW!

 

[Demented]

Did you watch the video? I didn't pay close attention to his calculations -- it was late when I watched and I may go back and watch again tonight -- but I thought he was using the design values for his calculations. He may have been comparing what the column was designed for to the load on it.

I did, but I have a hard time following subtitles that don't make grammatical sense at times.

It's been a long time since I've had to do any sort of maths on compression of a column, but I'm fairly certain it's more involved than the math done to get the total given.

Was any work to be done on the 'beam' at the 11" stepdown near Col Row 11.1? If not, and if the planter up against that change in elevation was to remain. then the building could have collapsed the day after the renovations were completed.

That entire section was due to be removed, inspected, and replaced as needed. There was a lot of language very specifically calling out replacing, not repairing.

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

 

[Demented]

But would they remove the planters? The planter where the crack may have developed was under one of the very wide planters.

Yes. The planters were cheaply thrown together CMU and painted. Nothing special about them. They've even been replaced, repaired, moved around over the years. Only a planter wall was to remain.

Also, in my opinion, the groaning noise at the end of the video isn’t the building collapsing but rather the table sliding across the floor.

Thats the sound of steel screaming before it snaps. Tensioning up just like a guitar string and bang. I've been witness to many destructive load tests of steel. It's an earie moan that'll wake any iron worker from a coma.

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

 

[SFCharlie]

Once again I call your attention to:
Watch Live: Champlain Towers South Recovery - July 12
where, if you slide back in time even a few tens of minutes, you will see one excavator passing cars to the left every rotation and the other excavator just taking huge chomps out of the pool deck. earlier in the day, the lighting was good enough to se the tail lights of a red car mid screen.
Study the days work.
Let us know what you catch.


SF Charlie
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[Demented]

Once again I call your attention to:
Watch Live: Champlain Towers South Recovery - July 12
where, if you slide back in time even a few tens of minutes, you will see one excavator passing cars to the left every rotation and the other excavator just taking huge chomps out of the pool deck. earlier in the day, the lighting was good enough to se the tail lights of a red car mid screen.
Study the days work.
Let us know what you catch.

No need for the torch or saw. Just rip the rebar out.
Nevermind. Going on 4 minutes of trying to start a saw.

That slab has been crumbling though. Sections of it look like large chunks holding hands with powder.

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

 

[SFCharlie]

origin of your user name, NOLAscience

Have you tried Googling "NOLAscience"? NOLA is obviously New Orleans LouisiAna. science is just science.

SF Charlie
Eng-Tips.com Forum Policies

 

[MarkBoB2]

Taken from the recent video found by Softee at

https://youtu.be/jI6Up5Nv70c:

Zooming in on the pile we get:

In the above close-up we see what appears to be an air conditioning unit from the penthouse roof surrounded by what looks like a ventilation fan, two parapet blocks, an anchor from the roof, and possibly the bottom of another anchor from the roof. There are probably a lot more parapet blocks under the pile, but one cannot be sure if just a few blocks fell or if the entire parapet fell. In the upper right there is another man-made object with sharp sides, but it is impossible to tell what it is. The following photo shows a close-up of the same pile from a slightly different angle.

In the above close-up we see what appears to be the same air conditioning unit from the penthouse roof with another air conditioning unit above it, with what looks to be a ventilation fan to the left of it, along with an anchor from the roof and the white arrows pointing to two parapet blocks. This time, however, we can see a hexagonal object with a pole protruding from it which may be the bottom of a deck table along with the mast for holding the sun shade. Again, at the upper right there is another man-made object with sharp sides, but it is impossible to tell what it is.

Looking at the same pile from 90° to the right, we see:

Zooming in on the pile again, we see the following closeup

In the above close-up, on the left at the top of the pile we see what appears to be the same air conditioning unit from the penthouse roof that we saw in the earlier close-ups. This time, however, it is clearly distinguishable. On the right hand side of the pile we can vaguely see more two man-made objects. The one on the top appears to be another air conditioning unit from the penthouse roof. The one at the bottom may be yet another air conditioning unit from the penthouse roof. The lightly colored rectangular frame lying over the bottom one may be the frame that held the two units when they were on top of the penthouse roof.

All of these units appear to be displaced from their original landing points on the floor of the parking basement because of the actions of the recovery crew that obviously cleared the basement floor. However, the fact that they have left the objects in this pile behind while clearing everything else appears to show that they believe these objects to have a special importance. So they are leaving them in place temporarily until someone else can inspect them.

What I infer from these objects being found on the floor of the parking basement and being left behind temporarily by the recovery crew is that these objects clearly fell from the penthouse roof before any buildings started to fall down and before the pool deck fell down. In other words, the falling of these objects from the penthouse roof was the trigger that started everything that followed, including punching a small hole in the deck, taking out one or two horizontal support beams between columns C27 and M11.1, which then caused column 27 to buckle, which probably caused the two adjacent columns to buckle also, bringing down the entire middle section of the buildings, then bringing down the other two sections of the building, and then causing the rest of the pool deck to collapse. These photos are as close as one gets to a confirmation of this general narrative.

Now we must determine why the penthouse roof fell down to start the entire sequence of events. This appears to be why Allyn Kilsheimer and his company KCE are taking cores from the penthouse and higher floors of Champlain Tower North.

 

[AutisticBez]

Its possible the deck and planters just gave way one day. They reached a set limit in their capacity to remain intact. Call it a "tits up" moment.

Its also possible debris fell from penthouse. Fits the timing with work done. Its also possible the penthouse work caused deck planters to fail.

Its also possible for a sleepy driver to hit a stationary column. I don't think the columns had any chance of withstand -any- impact.

 

[Demented]

Why do you all enjoy looking at photographs and videos that were filmed on a potato? Ya'll need the 480i version. If you keep squinting really hard enough, Nessie is in there.

Hardly better images, but man, those aint A/C units. Why must the internet compress images more? Damn you.



One of my old MS&E professors told the lecture a joke one time.

A group of engineers take a taxi cab to a convention together. (yada yada yada filler)
As they're driving through some farm land, the taxi driver says to the engineers "Hey, look at that cow with one eye!"
The engineers all turned, covered an eye with a hand, and said "where?"



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

 

[arbitraria]

I agree that the hired engineer has seen something to indicate a possible geotechnical issue. Especially since the recommendation was for buildings east of Collins Ave. Also the timing of the recommendation raises suspicion. If he was just being overly cautious, why not make the recommendation for geotechnical investigations at nearby buildings several weeks ago? What prompted the announcement yesterday?

Look on Surfside's document dump and read the entirety of "Properties East of Collins Avenue Structural Assessment Recommendations Letter". Geotech is just one of the areas they're investigating - the structural review looks to be incredibly thorough, there's a very detailed list of core samples they're asking for from each of these buildings. In addition to GPR for slab thickness and reinforcing layout, they want 3 slab cores for compressive strength testing and one more for chemical composition testing, plus a small core from a column. From the basement, first floor, third floor, highest floor, and roof. Among other site condition evaluations. That's one way to force the recertification issue, I suppose?

I'd guess they're seeing a multitude of potential environmental factors that are lending concern - subsidence, and maybe the effects of saltwater are proving to be more damaging in a shorter time span than originally anticipated? Perhaps the mixing concrete on-site with beach sand and/or seawater is looking less anecdotal, but a tangible concern for all these coastal buildings? (I'm in the northeast, I would have no clue, I'll defer to those of you with local experience on this one.)

I'm off to look at some screen caps of the video Softee linked, curious to see if the bent rebar at the base of the column remains give any more clarity to exactly how the building fell, since a good number of them look fairly distinctive. (That is if the mass of the collapse and subsequent debris removal didn't distort that evidence beyond usable observation...)