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

 

[Tomfh]

What is the procedure in that area regarding dewatering during construction? Are there established rules? Do people follow the rules?

 

[JoelTXCive]

I'm with Hokie. I think there is a lot to learn here.

In big accidents like this, it's rarely 1 single item that causes the failure; there are usually many contributing factors that all come together in the wrong way.

I would think the sinkhole aspect will be validated or thrown out rapidly; but all the other possible causes will probably take months to figure out.

After the Florida International Pedestrian Bridge, this is a 2nd large failure in Florida. I think that will motivate the public; who will then motivate the politicians on some substantial engineering changes. I would be surprised if there were not national implications.

We will be studying this collapse in college classes forever, just like the Hyatt Regency walkway collapse in the early 1980's.

I feel so bad for the families in that building.

 

[bnickeson]

After the Florida International Pedestrian Bridge, this is a 2nd large failure in Florida.

Don't forget the collapse of the parking garage from about a decade or so ago and the collapse of that outdoor deck that injured a bunch of people.

 

[geotechguy1]

When they do the root cause analysis I hope they add up all the money ever paid to real estate agents to sell the land and units involved and compare it to all the money ever spent on design, maintenance and inspection.

 

[mfgenggear]

Insurance will or maybe cover it.

 

[missstructures]

@JoelTXCive right on the money.. never a single issue. Sinkholes are unlikely in South Florida and that building is surely pile supported just like 95% of structures along the coast.

Here is some additional information, including name of firm doing the 40-year certification in link below.
Someone asked above if the enforce the certification, they do, but just like the rest of sad state of our profession, a lot of people don't want to pay for what i think is a big liability and responsibility task.

https://www.local10.com/news/local/...um=social&utm_campaign=snd&utm_content=wplg10

 

[epoxybot]

When you look at the debris field, you see columns and floors but not many walls. Link It explains why the debris pile is not higher, most of the walls are CMU, which can be seen here and there but likely a great deal completely crushed. Another reason, there isn't a lot of hope for finding survivors.

 

[missstructures]

@epoxybot that is very typical construction in S Florida, main structural system is concrete slab/columns/beams, shear walls at cores. Most of the masonry is "infill" only

 

[hokie66]

That bottom photo in epoxybot's post is intriguing. Are those black rods individual unbonded PT tendons? Are those closely spaced spalls where the tendons were? Is that photo of a tranfer slab?

 

[dik]

I'd also be looking at the detailing... there appears to be little redistribution.

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

-Dik

 

[warrenslo]

The building changed its HVAC equipment sometime after 2019. This equipment was on a red steel platform with corners sitting on concrete columns clearly visible in aerials. The equipment flipped over the platform as it fell down the building, this tells me it didn't ride down the building but may have been the reason of the collapse - falling first. The new equipment was on sitting the portion of the building that is still standing yet fell. There also is a large gash in the remaining portion of the building under where the equipment sat.

Furthermore, initial reports confused 135 and 136 units, it appears at some point the "Penthouse A" was added (possibly during construction) as the flyer from 1980 for the building only states 135 units and 12 floors. The penthouse is the 13th floor and 136th unit - it was recently sold and the listing noted marble floors. The penthouse and HVAC unit appear to share a column at the SE corner of the HVAC platform that seems to be the source of the collapse.

I wonder if they placed any additional equipment on or near the HVAC platform prior to collapse and if the building was structurally designed for the penthouse. It is also possible the platform itself failed if it was not designed for the new equipment - it does not look like they replaced or strengthened the platform when the new equipment was installed. To me, this does not look like a sinkhole but a progressive collapse from the roof for the first portion that collapsed as it did not tip over, followed by a failure of a low level (possibly garage) column due to debris causing the second collapse where the remaining building essentially tipped over on top of the first collapse.

Note: I have not been able to access assessor or permit info for this building on the town or county websites, it seems to be blocked - which is pretty unusual.

-W

2019 aerial (old equipment):

2020 aerial (new LARGER equipment):

 

[TheGreenLama]

hokie66, good eye. Those look like PT tendons that have been ripped out of the bottom of that slab as the area beyond came down. This spot looks to be at the juncture between the standing and the collapsed. The rescue worker seems to be standing on one or two floor slabs that have come down along with the PT. Area to right shows something similar with the PT still in slab. Although, the way those concrete blocks are dangling, and it being near the column, that could also be mild steel in the slab-column connection zone.

 

[spinspecdrt]

I'm not seeing any PT??

 

[JoelTXCive]

Dik - yes, what I keep wondering is how a localized failure event became a near global failure.

Whatever the failure mechanism was, it started local. Why couldn't those forces redistribute?

In the Oklahoma City bombing, half the building was blown off and it did not pancake. The same is true of the World Trade Center bombing in the mid-nineties. Both buildings took massive blows without total global failure.

 

[JohnRBaker]

It's being reported that heavy smoke is starting to come from the rubble, that it appears that there are fires burning somewhere under the debris.

John R. Baker, P.E. (ret)
EX-'Product Evangelist'
Irvine, CA
Siemens PLM:
UG/NX Museum:

The secret of life is not finding someone to live with
It's finding someone you can't live without

 

[Ingenuity]

That bottom photo in epoxybot's post is intriguing. Are those black rods individual unbonded PT tendons? Are those closely spaced spalls where the tendons were?

hokie66: No PT from my observations. I am seeing bottom rebar that has 'unzipped' from the slab soffit.

 

[Enable]

Doesn't it look a little too clean to you Ingenuity if those are direct bonded bar? I know the water has probably washed off a bunch but when I repair structures concrete is stuck onto rebar all over the place, even when it basically falls down from the slab. To see all those bars cleanly rip from the underside, it just feels like there was a greasing agent or something on the bars inhibiting the bond. Maybe not, but it's weird to my eye. Those bars look like new.

 

[Ingenuity]

Those look like PT tendons that have been ripped out of the bottom of that slab as the area beyond came down.

I don't think these are PT tendons.

No appearance of drape. No anchorages appear to have been ripped out. No one - not even in the 'evid-80's' - placed single PT tendons at 12" centers - always multiples bunched in flat groups at greater spacings.

Looks like deformations on the fallen/hanging 'bars' - so possibly rebar (that has unzipped from the slab soffit)?

 

[SocklessJ]

The lack of ductility here is truly striking.

I re-watched the video and it doesn’t look like a “pancake” type of progressive collapse. There’s a loss of support of one side the building which then radiates through the rest.

Regardless of what caused the loss of support, the structure should have been able to redistribute that load.

 

[JoelTXCive]

Where are the transverse bars? I guess the longitudinal bars (in this view) were on the bottom of the cage and they unzipped?