Hi-Rise Condo Building Collapse Near Miami Prompts Massive Emergency Response, At Least 1 Dead

[appalachiablue]

- Building Collapse Near Miami Prompts Massive Emergency Response, June 24, 2021.
An overnight partial building collapse prompts a massive emergency response in Surfside, Florida. NBC News' Sam Brock has the latest from the scene.

NBC, 'At least 1 dead after high-rise condo building partially collapses near Miami Beach.' Rescue crews continued to search for any survivors after a massive emergency response to the incident in the town of Surfside...
https://www.nbcnews.com/news/us-news/rescuers-rush-partial-building-collapse-miami-beach-n1272216

[jaxexpat]

1. Steel-reinforced concrete fails over time in a sea salt environment without occasional remediation.

Without hearing of an initial explosion at this time, I'm guessing that's the culprit. If there is visible deflection on the outer surfaces of steel-reinforced concrete, the underlying reinforcement steel adjacent to these deformations is usually, nearly 100% compromised. In concrete multi-story construction, veritably all concrete above the ground floor is steel-reinforced concrete. Just a tip, if you live in a concrete structure, structural damage may be observable prior to disaster. Exterior decks/porches are usually the first to show signs, especially where the floor slab adjoins the vertical wall or pillars. It happens in non sea-exposed areas as well and to a lesser extent. Sea salt will, over time, migrate through microcracks in concrete during rain/fog events. When it accumulates onto steel within the concrete, the chemical process, which ends as rust, begins. Rust expands/swells the area of the steel causing adjacent concrete to disintegrate which shows as deflection in the exterior surfaces. Similarly to how freezing water will expand with great force to break strong encasements, so does rusting re-bar steel break concrete.

Remediation is possible, to an extent, but is very expensive in engineering, tools, materials, equipment, labor and non-habitability during the work effort. There is a cost/benefit equation which is nearly impossible to determine until remedial exploration has commenced.

Again, I have no proof or evidence that this is what happened here nor am I, in any way, saying this is the case here.

[appalachiablue]

2. That's very good info. I'll pass it along, thanks.

[mopinko]

3. strapped on balconies have always struck me as a bad idea.

they are ubiquitous in condo conversations here in chicago.
bolted on to 100+yo masonry buildings. freezing and thawing and heating up over and over and over again.

never ceases to amaze me the loose grasp some architects have of the rules of physics.

[jaxexpat]

4. I've heard engineers called "architects with no imagination" by architects.

And architects called "engineers who failed the math curriculum" by engineers.

Ultimately, it's a thorough understanding of materials which makes the best designer.

[mopinko]

5. both pretty much true in my experience.

the number of architects that cant put a rainproof roof on a big building never ceases to amaze me.
yeah, i'm lookin at you, flw.

but also some of chi's best firms. the washington library, the sulzer regional library, the state of illinois building- all took years of work to be able to put the buckets away.

[BlueWavePsych]

6. Rising seas eroding foundation? Climate change?

Nah

[Warpy]

7. That is my best guess, right there

Last edited Thu Jun 24, 2021, 04:04 PM - Edit history (1)

The part of the limestone they'd sunk the pilings into destabilized over time.

WFOR's coverage mentioned the building had just begun a top-down inspection. I have to wonder if that was ordered because residents had started to notice cracks and doors that wouldn't close properly.

Buildings that collapse usually give some warning.