fastom

The video doesn't lie, it's just you are misinterpreting the reason the walls are moving. They are being pulled in. It has nothing to do with any contraction... and by the way weren't you earlier saying that the floor beams just sat a narrow ledge and fell off? If so how can they pull in a wall?

More likely the floor joists are firmly anchored to the walls and pulled in the walls as they were blown to smithereens and dropped into a big hole newly created inside the building.

You can't seriously think metal contracts THAT rapidly or that much. And for what it's worth i worked in a blacksmith shop for several years and am well versed on properties of heating steel and iron.

That MIT video is not only very long it's also covers stuff you can learn by trial and error like i have. His plot on the temperature vs expansion isn't exactly right, there is point where it won't expand further with more heat. You can shape the direction of expansion by heating in different areas. Heat rises. It's true a piece of steel obstructed or restrained will warp like in your railroad track example.

But back to the case at hand, the beams never could have got close to hot enough to do any of that.