You should provide a link to that steel building collapse. Maybe I was wrong in that it was a "tower" not just a building.
Good questions, answer them yourself if you care about the US Constitution.
I've built forges and used them. You can barely get steel orange with it using wood fuel. I had to use coal and coke to get it cherry and really workable. As you can see, even a charcoal fire with forced air, none of which was possible on 9-11, is absolutely needed to get steel red hot. Not that it has to bee that hot to cause a failure but those failure temperatures are not going to be spread over enough area to cause anythign like what happened.
http://www.survival.com/forge.htm
Step two: Construct a charcoal kiln.
Charcoal is virtually essential to a wood-fired primitive forge. While forging temperatures can be reached with hard wood fires and a good bellows, we had only Ponderosa and Lodgepole pine, woods that are too soft to get the really hot fire we needed.
Step three: Construct a bellows and Forge.
Airflow is crucial to a forge. Air, fuel and fire create heat and we needed lots of air to make our camp-made charcoal into a viable heat generator. The closer we got to fission the happier we would be. One of our members, Ray, came up with the ideal solution. Using a heavy-duty trash bag and a flexible fiberglass rib found at a hunter’s camp, he made a huge bellows. Attached to the bottom of the bag and held in place with junk wire was a hollow Elk leg bone.