What Happened in the Surfside Condo Collapse?

Even earthquakes aren’t supposed to bring down concrete buildings. So how did the Surfside Condominium—a modern building built in 1981—fail?

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Credits:
Executive Producers:
George Zaidan
Hilary Hudson

Producers:
Laurence Vuckovic
Andrew Sobey
Darren Weaver
Elaine Seward

Host:
George Zaidan
Sam Jones, PhD

Writer:
Andrew Sobey

Scientific consultants:
Michelle Boucher, PhD
Maria Juenger, PhD
Brianne Raccor, PhD

Sources:
Champlain Towers structural field survey:
Quotes from the top half of pg 7:
"failed waterproofing is causing major structural damage"
"concrete slab is not sloped to drain... This is a major error in the development of the original contract documents prepared by [the architects]"

Ex-Maintenance Manager for Surfside Condo That Collapsed Recalls Saltwater Intrusion

Composition and density of nanoscale calcium–silicate–hydrate in cement

Steel Corrosion

‘The building was in OK shape.’ The upscale condo near Miami Beach still collapsed.

[ACSReactions]

The concrete curing process actually gives off heat. If you decided to pour yourself a pair of concrete boots (don't, but hypothetically speaking), they'd feel quite warm from all the energy released as calcium silicate hydrate forms.

[dianewallace]

Thank you. I had heard salt water flooding may have caused the collapse but now I understand that this particular building's concrete foundation may have allowed salt water to reach the steel inside the concrete.

[edsalinas]

One of the demolition crew members said that as he was drilling a hole in order to place the explosives to demolish the rest of the building, he noticed that the concrete seem to be a bit soft.  As if the construction team had used a lower PSI strength concrete.  We definitely have to take this in to account.

[retiredjedi]

I was staying at Solara Surfside, it's the 7 story building next door to the tower. I was sitting out on the balcony, watching the ocean and noticed cars pulling out of the basement from the tower. After a hour or so I noticed every car left a water trail and it had not rained for days. This was around 10 years ago

[ka-mai]

I don't think I ever saw any concrete curing under water or tarps in my country, and well, the roads and walkways often are... not great, they tend to "sway" a lot after a while. I'm not gonna think about the buildings now, no sir.

That aside, loved George's presentation! And everything in the video was clear and easily understandable, thanks team Reactions!

[teoengchin]

While corrosion of rebar due to saltwater exposure might be a contributing factor, its unlikely to be the primary factor. All the buildings around the Surfside have been subjected to the same salt water exposure, and Champlain Towers South is not the oldest building in the area. If the saltwater exposure was so severe to be the primary factor, then older buildings in the same area would have collapsed first. From my understanding, there are buildings there from the 50's and 60's that are still standing, and no other building have been assessed to be in danger of collapse.
Unless other buildings in the area also start collapsing, the primary cause will likely be something unique to Champlain Towers South.

[iancormie]

Sooner or later, economics (or building codes) will dictate the replacement of steel rebar with bassalt, fiberglass or some other reinforcing material.
2 inches of concrete has historically been used to rebar cover but in marine environments, it is a question of when the salt attacks the rebar rather than if that attack will occur.
Ask anyone who has worked off-shore how corrosion invariably attacks everything.

[shiroineko]

Interesting. When the steel bars rust they expand. That does sound like very bad news for the surrounding concrete.

[drewofearth]

Does anyone have a read on concrete inspection? When I visualize the future of certifying concrete structures, my brain goes to ultrasound readers.

[jeffhochheimer]

I think the Tupperware people will want to have a word with you.

[adamarlem]

The public areas were built at 100psf, whereas the private at 400psf. The west side with valet, office, elevator, utilities, etc was at the west "public"; the more luxurious private, larger were on the east.

[lockbert]

The inspecting engineer said the pool deck was not draining and I believe blamed it in the architect. But that concrete pool deck had sloping concrete to frequent drains in the drawing. But, it was covered with pavers in 1996 and that effort could have very well screwed up the drainage.
A better maintenance contractor would have helped as well. They had water leaking into the garage for years through the concrete ceiling and someone was coming out and working on it, but not fixing it. Or even realizing how dangerous it was. There was plastic on the ceiling of the garage whose purpose was to direct water coming through the ceiling away from the car parked below it.

[hibahprice]

Fun fact, the less water in concrete, the stronger it is. Concrete at the construction sites of high-rise buildings is almost like flakes that have absorbed all the milk, the main thing is to keep this minimum amount of water for as long as possible .. so that there are as few cavities inside the concrete as possible. For this they seem to use silica or something similar.

[Oddman]

One fun fact about concrete that is not really on-topic for Surfside BUT is worth remembering is that sugar will keep it from curing properly. I work in a concrete precasting plant, and we have to keep sodas away from the casting beds. One can of coke will ruin an entire yard of concrete!

[IrvineTheHunter]

Something I feel was missed [or at least I missed] was steel has a different thermal coefficient than concrete, point being the steel core expands and contracts separately from it's concrete shell, and because concreate has extremally low elasticity....

it leads to cracks that lead to seepage and rust that leads to cracks and structural failure.

[MaryAnnNytowl]

Important information to have. Would be nice if people could easily access the information about previous reports of trouble with the buildings & the building materials - for example, the company that pours the concrete, the source of the concrete and steel, etc. - so they can make informed decisions. 🤔

[sundaywhiterabbit]

You all should be exploring the science of controlled demolition.

[theodorejay]

Poor design, shoddy construction, & neglect unfortunately killed almost everyone in the building. It's a wonder this doesn't happen more.

[sircampbell]

Where the Video from the Cameras on Building ?

[trafficjam.]

if u have that as a possible theory, wouldnt that likely b tru about other buildings built in that time period in that area? that wuld b a huge mess