Miami Beach, Champlain Towers South apartment building collapse, Part 02 151

[dik]

thread815-484587


Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[Kreemerz]

Just sharing this theory in animated presentation.

https://www.youtube.com/watch?v=hynHiWE818c

This engineer is going with the idea that the pool/patio deck collapsed pulling the beams toward the deck causing the main sections of the condo to come down.

Looks plausible but not exactly sure what caused the deck to collapse first.

 

[saikee119]

Seppe (Structural),

I note your disagreement with warrenslo who suggested the top few floors might have collapsed first while your argued the whole stack of flats could sink bodily downward.

I believe Warrenslo had mentioned some lights at the lower flats were still on (think I could make out at least 4 windows with light on). If that photo depicts the building when the collpase had commenced your suggested the whole stack going down bodily will not be credible. This is because when a flat shears a couple of levels downwards all the electrics would have been severed.

I believe warrenslo's theory has merit if a significant amount of the roof dropped onto the next level overloading it to fail sequentially. This was the exact failure mechanism of the two World Towers in 9/11. Every enigineer who has designed a building would know we never design one floor to carry the dead load of two floors in a normal building.

Warrenslo's evidence has not fully convinced me yet but I think it is entirely possible workmen doing work on the roof could have inadventently weakened some parts of this old structure, like intercepting a few rebar while installing attachments and fixings, to trigger a failure. To me it is more important to establish if it was indeed the collapse was initiated from the falling of the top two of three floors.

We engineers may be smart and thoughtful but our designs are always executed by the workmen who are not trained to think or to be careful like ourselves. Remember not long ago we have workmen initiated the collapse of the FIU footbridge not far away. The workmen was applying post-tensioning work as instructed by the engineer. Some of them died with the falling bridge.

 

[saikee119]

Kreemerz (Computer),

I have two problems with the animation and theory.

(1) The pool deck was empty in the middle of the night but there was a huge unknown force acting downward and big enough to cause punching failure of a 9.5" thick slab by at least 6 columns. Where did this huge downward force come from?

(2) The deterioration of concrete is by water leaking into the surrounding concrete. The photos and reports showed the deterioration surounding the the pool wall at the garage level. It is high unlikely the water could drain upward to damage the pool slab elsewhere when it is is the ceiling of the garage. There is also no photo and reports citing pool deck damaged at connection of the pool deck with the columns where punching shear occurs. The columns did suffer damage by ponding of water at the garage base level though but that doesn't fit in with the animation/theory.

(3) Despite being reported corroded and damaged the pool deck surrounding the pool did not collapse but is still upright and not in distress.

 

[BlakeStr]

Running with the post by Warrenslo that the top 3 levels collapsed first, along with the fact that there was an on site crane lifting roofing materials onto the roof the day before, there is a good chance the roofer overloaded a section of roof with materials. Also, on concrete slab roofs it is common to use a small track bobcat to remove existing roofing and save on labor. A Bobcat MT85 is commonly used and weighs about 3200 lbs empty. Also, it seems common amongst demolition workers, that they like to stockpile waste removed materials in large piles weighing several 1000 lbs.

 

[BlakeStr]

According to the original drawings, lower strength concrete was specified in the columns of the top few floors.

 

[Kreemerz]

There are cameras on that pool deck. Multiple cameras.

Wonder who has that video... I imagine some or all of the video is stored in the cloud?

 

[Mark R]

Miami Beach, Champlain Towers South apartment building collapse, Part 03 , Thank-you.

 

[BlakeStr]

This USA Today article says a crane had been at the building.

https://www.usatoday.com/in-depth/g...g-collapse-investigation-underway/5333761001/