[stockpirate]

To those who say “Jet fuel doesn’t melt steel” I say, “Jet fuel burns at about 1,200 degrees, At 1,000 degrees steel looses 70% of it’s strength in 30 minutes. That means steel beams designed to hold up 1,000 tons of concrete flooring will only hold up 300 tons. The result is structural failure”

That is all.

[smileyface]

Building 7

[Cletus.D.Yokel]

And the flex-bands, designed to support the sway of the building in high winds were made of Aluminum.
700F

[Pete from Shawnee Mission]

And this is correct. Steel does not need to melt to fail. With time and heating it will deform to the point where it cannot support a load.

Heat also affects concrete. "Failure could occur from loss of bending or tensile strength; loss of bond strength; loss of shear or torsith ional strength; loss of compressive strength; and spalling of the concrete."

(https://search.brave.com/search?q=effect+of+fire+on+concrete&source=web)

Floors start to sag, concrete fails, active loading becomes kinetic loading.

When floors pancake down, air is rapidly expelled or puffed out of the building. If it contains jet fuel or diesel fuel or smoke or the burning products of combustible material the collapse creates the illusion of explosions going off on each floor.