Can you prove to yourself that open air fires really can make steel structures weaken & collapse? Try this!?
If what you are saying is true, then why is every single steel-frame building in the Western world built with fire-proofing around the steel? Usually the fireproofing is gypsum, although years ago it was concrete. Why do they do that? Why does everyone spend all that money in fire-proofing the steel? The answer is that your arguments are wrong and that steel IS highly vulnerable to fires. Period. Even the world trade towers were fire-proofed. Unfortunately, the type of fire-proofing they used was “blown on” & came off too readily. You’re making an argument that contradicts what every civil engineering book says. It contradicts the way every steel building is constructed. Also, there are dozens of photos, taken just before collapse, that show the steel columns bending.