Partial Collapse of 12-story Condo Building in Miami

[MrPrena]

Salt air and concrete?

Very possible.
That is my 4th and 5th guess.
Some building that fell like this had salt water and concrete mix.

[rondog]

I read there's speculation about a sinkhole too. And that was 2mm per YEAR, they say about 3 inches total. I could be off on that, read it hours ago.

[BushMasterBoy]

The salt air is very humid there. A Galvanic reaction occurs to the rebar due to dissimilar metals mixed together, calcium and iron. Iron in the rebar and calcium in the concrete, the salt in the humid air makes an electrolyte. I think the rebar they replaced in the condos I lived in was coated in epoxy. They only replaced the outside decks above me. I was on the ground floor. My deck seemed OK.
Cocoa Beach Surf Company built a parking garage next to the condos. It was made of precast concrete beams with galvanized steel cables tensioned by giant fasteners(nuts). They trucked the beams in whole. The entire structure was settled on pylons pounded into the sand. I would park my car there during hurricane evacuations. The parking garage was always unscathed by the storms. The car was covered in a 1/4 inch of salt!
Aerial photo of where I lived in Cocoa Beach. Parking garage to the left of tennis courts and condo to the right. It is easy to see the precast concrete beams of the garage even from the air. Every time I returned from a hurricane evacuation, some buildings in the city were destroyed.

[rondog]

Yeah, fuckabunchaFlorida - I've lived and worked there, no desire to ever do it again.

[Aloha_Shooter]

now it sounds like it was known that the building was "sinking" for at least a couple of years. Built on or in an area that used to be wet lands. SO, settling over the years and finally a total collapse? If someone knew that the building had been settling/sinking, it sure smells like a lawsuit in the making.

I recall reading something about it sinking by 2mm. That's not like it's disappearing into a bog.

No matter what it was, there will be lawsuits.

The other thing that happens is people willingly sign waivers when facts like this are disclosed at sale or lease. They often only care that the price or rent is cheaper and don't consider why or if they do understand why, they're happy to roll the dice figuring any disaster that happens will likely occur after they're gone. When it DOES occur, they then scream "I didn't know" and "someone needs to take care of me" -- and the leeches lawyers are more than happy to swoop in and start a class action lawsuit.

[clodhopper]

Yeah, fuckabunchaFlorida - I've lived and worked there, no desire to ever do it again.

same.

[FoxtArt]

FTR, coated rebar fails far worse and usually far sooner than coated rebar. Because it rusts behind the coating anyway, it just ends up de-bonding from the entire application (the coating is bonded to the concrete, not the rebar, the rust debonds the coating) and then the rebar has no resistance to extraction forces at all. Uncoated just swells, but stays fully bonded.

It was a good idea in principle, but fails in execution because it is impossible to keep the coating from being damaged during install. Only stainless rebar (yes, it is a thing) actually prolongs the service life in high chloride ion environments.

ETA: That said, I doubt salt has anything to do with this collapse. It is most likely something geologic, such as a sinkhole as suggested or a number of other possibilities.

[Delfuego]

or a number of other possibilities.

Hillary Clinton?

[FoxtArt]

Hillary Clinton?

I had a wisecrack ready about the building having something on her but it's below the threshold of class, and I also like life.

[def90]

Yeah, coated rebar is being phased out and banned in some situations, if you nick the coating during installation or if there is a pinhole during the manufacturing process the rebar can actually erode at an accelerated rate in a matter of months in one specific spot rather than a slow all over erosion that could takes decades or more.