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A comment on Condo wreckage hints at less steel in columns than design drawings. Parent comment

Re:Condo wreckage hints at less steel in columns than design... by aaron695 on Sunday July 04, 2021 @11:46PM (#27734477)
The coldest is a bit after dawn. So the previous dawns should have stress tested it. It should fail when the stress is around maximum under this Hyatt peak theory.

Max rate of change of temperature is sunset and sunrise. Rate of contraction I'd expect similar?

I'm not sure AC would change the thermal mass of a building much. One cubic meter of air weights 1.2kg. Changing the concrete walls would be hard.

A drunk hitting a pole at speed in the carpark would fit perhaps. Drunkenness to an empty carpark would be high.

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Re:Condo wreckage hints at less steel in columns than design... by Scoundreller on Monday July 05, 2021 @01:38AM (#27734914)
> The coldest is a bit after dawn.

The building (and deck surface) will continue to radiate heat throughout the night on a clear night, especially with few obstructions like a waterfront building has. That's how crops can frost with airtemp > freezing, and why the guidance is to cover your plants. It's not to insulate them against convection.

Counterintuitively in this scenario, this effect is greatest when the wind is calm.

https://en.wikipedia.org/wiki/Radiative_cooling#Architecture

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