Miami Beach, Champlain Towers South apartment building collapse, Part 08 20

[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

SF Charlie
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[Optical98]

The Gonzalez family Unit 904 -

https://www.nbcnews.com/news/us-new...ld-not-be-alive-after-condo-collapse-n1273597

Brief facts in a nutshell version -

They ran out the door, got 5 feet and that slab dropped one floor. The mother had enough time to crawl over and get on
top of her daughter to try and protect her. 5 seconds...10? Then they dropped from 8th to 3rd floor.

That last line about the daughter is tough.

And somehow Binx their cat survived too!

 

[Optical98]

LOL Demented....are you ghosting my computer? j/k, but we often post virtually the same thing..

 

[Demented]

Have we any indication of where this cable in the steel support permit denial is, and if it did have a turnbuckle attached? Where would this cable have been anchored?

Edit: Ha, nope.

 

[Optical98]

Demented, a cable attached to the AC unit? I know I saw a picture that showed a bit of it, and later a hole where I assumed it was yanked out. I'll try to find it.

 

[Demented]

Seems that was the plan for the denied permit. Was it just held down via tensioned cables anchored to the building? Maybe thats what the tearout on the remaining beam atop the column we see in the controlled demolition. The thing from the other side in the drove video we know had no rebar in it. Plus that field report. That would be an ooopsie. A lot of oopsies.

 

[Optical98]

This pic is before the new unit, but I think u can still see it on the new set-up too.

 

[Demented]

That would appear to be a PVC drain. It's more visible in the 4k drone video.

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

 

[Optical98]

This is the hole after, yeah potato pics...I can't tell cable from pvc....

 

[gonefishing2]

Demented, PVC Drain with Trap you see in satelite photo

 

[Optical98]

Bottom left?

 

[gonefishing2]

I find this photo interesting, in that there is no concrete beam at Penthouse Corridor like there is shown on original Plans, and even on revised original plans. This Penthouse Addition was changing on the fly, IMO.... Originally there were 2 concrete beams spanning columns at each end. 2019 Photo shows one end of platform hanging off West CMU Penthouse corridor wall.

Could their 'Value Engineering' have eliminated the 2nd concrete beam, by just hanging off CMU wall? Photo as-built does not match any version of original design I could find.....

Edit notice column line on left of hanging AC supports

Here is one version of AC support beams, and I will look for plan that has revised 1980 date too.

 

[Murph 9000]

We also have the elevator in use at the time, pulling a heavy load up from the roof.

With only two people in it, the elevator should have been falling upwards, controlled by motor braking. Properly configured, the counterweight should balance the elevator car at roughly half load, so they fall upwards when lightly loaded. All of the weight for it should have been directly supported by the RC shear wall structure, and it shouldn't have been putting much dynamic load into the building as a whole.

 

[Demented]

@Thermopile
That was my thought exactly.
Loss of support. F=MA
This support was to stop the roof collapsing.

The steel beams look like it's held with the typical 4"x4"x.25" steel clip with 7/8" slotted holes to accept a 5/8" Hilti anchor.

@Murph9000
Thank you for explaining that.

 

[gonefishing2]

#Demented, And failure on West side AC area would be hidden by East Penthouse Corridor Wall in the Security Cam video.

Edit, Slab could have failed under CMU West penthouse wall, well before columns actually failed with AC load on CMU wall and not column line

 

[gonefishing2]

Notice Revision 1 and 2 from Oct 31, 1980 and Nov 11, 1980.... Very fluid changing design, and perhaps pressure to get done ASAP... Sorry this is AC4 I posted. You can find it in several of Surfside PDF's both with the revision dates above

 

[Demented]

@Optical98
That hole is the trash chute vent. 5/14/80 Rev date Penthouse addition plans. SHT 4 of 9

 

[gonefishing2]

Why extra steel beam on top of steel beams sitting on concrete beam on one end, and hanging on CMU wall on other end?

Was extra top steel beam, a bandaid fix for failing concrete beam in 2009?

 

[Demented]

The permit was requested AFTER the new install. I think the unit may have been overweight for the structure. We could already see the fabricated beam had a slight arch to it, and the weight was hanging from it if that concrete beam was considered inop for what ever reason. This severely changes the load capacity of the beams with their construction.

The extra top beam was the temporary support structure to eliminate shoring of 3 floors down during the beam replacement. It was to have no load bearing capabilities. It was just to hold the unit up while the beam was replaced from end to end. The portions left on the column should have been tied into the new beam, but seems they were not properly. This could very easily lead to a shear of the concrete beam due to overloading and uneven pressure being applied by an overloaded and sagging steel beam on very suspect concrete.

Edit: Time to go dig the spec sheet out for that concrete repair.

 

[gonefishing2]

#Demented, Correct the AC support beams are now hanging off cross steel beam on top, and resting directly on top of column lines of possibly failing concrete beam

 

[Demented]

Maximum 8" depthing. In regards to permit 09-00000261