51 people unaccounted for after apartment block collapse in Miami

[Mister44]

Make sense, especially for earthquakes.

[CCinBmore]

@Skeptic

Doesn’t the rebar in concrete sometimes rust and damage concrete over time because rust expands?

Heck yeah. That’s one of those “deteriorating factors” I was referring to. However, intact concrete that was properly built (amount of “cover” of concrete – how deep the steel is within the concrete – is key) is very stable from this perspective. A chemical reaction occurs between the concrete matrix and the steel forming a passivating layer on the steel that prevents corrosion very well. It takes something to begin corrosion - inadequate cover, cracks that allow water penetration, chloride ion penetration (i.e. salt - happens with road salt in parking garages and could have occurred from the salt air environment in this situation), etc.

[Tribune]

CBC updated the story and changed the pictures illustrating responders. I may dig though later. The truck next to it was Miami but all I remember of the Collapse Unit Truck was that it said Collapse Unit.

@gatto that makes sense.

[anon87143080]

There are many teams in Miami that specialize in collapsed structure rescue. They have a lot of structures flattened by Hurricanes.

I used to participate in training exercises with Miami-Dade Rescue 5. Many of them also worked over in Haiti after the Jan 2010 earthquake. Phenomenal group of experts.

[jerwin]

@Tribune

Does this happen often enough to warrant this or is the Miami infrastructure just so large that specialized response units exist?

If a structure collapses-- because it wasn’t built well enough, or because the integrity of the building is damaged by fire, or an explosion, or because too many people crowd onto a balcony, or it was rammed by an out of control truck, the equipment needed to safely deal with the situation is often specialized or heavy. Why not put it on a special vehicle?

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[evilkolbot]

@anothernewbbaccount

Bucks which will be in short supply when rebuilding is needed at a cost of many times what the maintenance would have cost.

Maintenance money is money I don’t get to pay myself now. Rebuilding money is money some other schmuck can’t pay himself in the future. It’s win-win.

[CCinBmore]

@evilkolbot

Maintenance money is money I don’t get to pay myself now. Rebuilding money is money some other schmuck can’t pay himself in the future. It’s win-win.

Username checks out.

[jerwin]

@evilkolbot

Maintenance money is money I don’t get to pay myself now. Rebuilding money is money some other schmuck can’t pay himself in the future. It’s win-win.

That sort of attitude can increase your liability.

Be sure that your avariciousness does not become willful and wanton.

[dreamofthedarkstar]

I think the title needs to be updated. According to my local news, there are 159 people who lived in the building who are missing.

[David_Guilbeaul]

@CCinBmore

That’s one of those “deteriorating factors” I was referring to. However, intact concrete that was properly built (amount of “cover” of concrete – how deep the steel is within the concrete – is key) is very stable from this perspective. A chemical reaction occurs between the concrete matrix and the steel forming a passivating layer on the steel that prevents corrosion very well.

Back in the 1980s the telecom firm I worked with had a plant in a 26 floor office building. Because where we were situated we had access to uncladded concrete structure, I saw all these lurid cracks and thought, “that doesn’t look too good…” So, off to the Library and the civil engineering section. New appreciation for concrete, rebar, and engineering. Fascinating subject.