Maybe Huntsman can explain what it takes to get 47 tempered steel columns to lose all their strength and fall freely instantly.
Here is a clue. Which is most dense?
I can, actually.
Because the columns were tack welded together, so the joins were weaker than the steel.
The steel gave when
several floors fell onto the damaged sections, and from there it's like toppling building blocks.
You can do an experiment at home. Take a board, and stack ten wooden blocks (the rectangular kind) up longways to make columns. Support your board on theose columns. Add weight to the top. If you have it balanced right, the columns are fairly sturdy because of the weight pressing them together. You really only need very light support (small pieces of tape, say) just to make sure the wooden blocks are lined up with each other.
Now, get a coupl eof the blocks (say the ones about 80% of the way up) and replace them with something else, rolls of paper, say, to simulate the damaged steel columns. Then put your weight back on.
Let me know what happens.
Now, your reinforced concrete is a whole different story. That's more like using columns made of modeling clay, wrapped with chicken wire.
The steel columns are, typically, less likely to fail due to most causes, but when they fail, that's it. It's gone.
