Miami Beach, Champlain Towers South apartment building collapse 151

[bugbus]

Partial collapse of 12 storey apartment building in Miami Beach:

https://www.google.com.au/amp/s/

http://www.dailymail.co.uk/news/art...-building-collapses-sparking-huge-search.html

Was built in 1981. Not much information as yet.

Building profile:

https://www.miamiresidence.com/surfside/champlain-towers.htm

 

[SFCharlie]

The Miami Herald is doing it's usual job of excellent reporting and asking "experts"
See what experts say is the probable sequence of collapse at the Florida condo tower
To go to the 3d model directly:
Champlain Towers South
Less than I expected, but for the time being useful.

SF Charlie
Eng-Tips.com Forum Policies

 

[FacEngrPE]

The National Institutes of Standards and Technology (and it's predecessor National Bureau of Standards) have had a presence in building sciences since it was founded. They have a standing working grout [link

https://www.nist.gov/disaster-failure-studies/national-construction-safety-team-ncst

]"The National Construction Safety Team"[/url] that is chartered with responding to building disasters. This is the team that generated the official report on the WTC collapse.
Nothing specific on the current event is posted on the NIST site yet.

 

[dik]

Some quick comments...

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

-Dik

 

[Jon43442]

Good photo of the pool deck area post-collapse:

 

[Mark R]

What's interesting about that photo is at it shows the deck dropped straight down instead of pulling away like has been discussed in some of the potential sequences. If it dropped straight down it probably means that it's not a contributing factor to the actual collapse rather it's just a result of the collapse.

 

[dik]

The phonecall would indicate otherwise.

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

-Dik

 

[799931]

It dropped minutes before the building went down, it was a contributing factor

 

[Mark R]

The phonecall would indicate otherwise.

I agree but physical evidence is much better than evidence from untrained views of the situation while it occurred.

 

[spinspecdrt]

https://www.townofsurfsidefl.gov/docs/default-sour...[/URL]]

Very interesting that the majority of structural retrofitting (add drop panels, columns, etc) is in areas that didn't collapse!

It's seems the 40 year inspection system was working. The issues were identified, the plans were being created. I guess the lesson here is 40 years is too long.

 

[dik]

Sometimes, maybe... but the phonecall is pretty solid.

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

-Dik

 

[Engr1888]

The building is very close to the shore line. I heard speculation about sinkholes. If that's a possibility, very likely sinkholes may have occurred previously in the lawn fronting the building.

 

[Jon43442]

Alleged photo of cracking on first floor from Jan 2021 Google Street View (though hard to really see).

https://imgur.com/gallery/lvlxnr6

 

[Spartan5]

A resident on the 6th floor (unit 611 in the first portion to collapse) was awoken by the initial ground level failure, saw a two-finger wide crack run up the wall, and managed to get out of the building before it collapsed.

Monteagudo, who is in her 50s, woke up from a restless sleep and heard strange noises. She initially believed they came from the open sliding door to the oceanfront balcony.

“I ran and tried to close it but I couldn’t, I imagine because it was unlevel already because of all the movement,” she recounted. “I heard a crack and when I looked, I saw a crack traveling in the wall two fingers thick. Something told me, you need to run.”

https://nypost.com/2021/06/26/florida-survivor-recalls-escape-from-collapsing-condo/

Video interview (en Español):

https://www.univision.com/local/mia...te-el-colapso-de-un-edifico-en-surfside-video

 

[Murph 9000]

If it dropped straight down it probably means that it's not a contributing factor to the actual collapse rather it's just a result of the collapse.

Even a perfect vertical drop is likely to do a little damage to the column as the joint detaches. It's not difficult to see a mostly vertical drop giving the columns a little kick or pull at some point between detaching and landing on the slab below. The doubled vertical span has much less safe capacity, and probably has a bit of fracturing at the mid point. There's a fairly big chunk of energy moving around as that slab fails and falls, regardless of the precise way it falls. The column can't just let go of the slab, there's forces and release of both tension and compression as it happens.

If the structural system as a whole was a bit too close to limits, a little extra damage could be all that's needed for the next step in the progressive failure.

Combined with multiple witnesses reporting the pool deck failing first, it's likely more on the contributing than result side of the collapse.

 

[Mark R]

Alleged photo of cracking on first floor from Jan 2021 Google Street View (though hard to really see).

https://imgur.com/gallery/lvlxnr6

Hard to see is definitely an understatement! You could have easily seen cracks of some type but you certainly can't distinguish whether they are just cracks in the stucco surface or if they are truly structural cracks.

 

[spsalso]

A timeline for this event is going to be very interesting to see.

It seems that the time of the main collapse could be picked off of the video recording we've seen.

For the pool deck, I wonder if something might show up in the electrical metering record, or maybe some kind of alarm system. I imagine the garage was piped for fire, and that the pipe broke. That might give a time stamp.


spsalso

 

[adamewood]

Responding to Ingenuity's post, please correct me if I'm wrong, but it seems column I-10 was originally designed as an interior column. At some point the decision was made to not construct this extension, making column I-10 an exterior column. Depending on how late in the game this decision was made, makes me wonder if it was ever analyzed for the increased live load distribution? Or was it simply a matter of "it's carrying less trib, therefore OK" ....then add in the planters installed on the corroded plaza-level slab. Is it possible the column was overloaded?

 

[rapt]

Dik/Waross,

The terms you use, freeze and thaw and de-ice, are foreign to Australians for construction. Freeze is how we preserve meat. Thaw is what we do before we cook it. De ice is what we put in de glass before de whisky.

 

[Kreemerz]

Just incredible that people were walking by this on their way to their bedroom without any concern or alarm...

I'd be checking on the ground beneath it to see if there is any debris. That alone would certainly get my attention.

Is this part of the structure that is still standing? or another separate building nearby?

 

[dik]

Same here, as far as meat...

In some northern or very southern (polar) areas there are several months where the temperature falls below freezing 0deg C (32F). At the beginning of winter and at the end, the temperature fluctuates where the temperature is above and below freezing. These fluctuations are called freeze-thaw. With moisture in concrete, this alternate freezing and thawing causes deterioration called freeze-thaw damage. We use air entrainment in the concrete to minimise the damage.

Because of ice on the roads during winter, some places use a mixture of salt and sand to provide traction. This is called de-icing salt. The salt causes corrosion of reinforcing steel in concrete structures. Damage caused by corrosion in minimised by using a high strength concrete, admixtures and thicker concrete cover to the reinforcing.

Hope that explains it...

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

-Dik