9/11 Debate

[LP]

LP, the mass of that part of the building below the fires would have offered huge resistance to the floors falling from above, even if the fall had started instantaneously, i.e. were vapourised. Have you done the calculations taking that into account? Say 13 or 14 floors falling on top of the rest. Are you assuming the steel throughout the whole building had failed?

[member=36]cookie2[/member]  Most buildings are basically eggshells or hollow wire frames with central/internal supporting columns, not solid like the pyramids. Those columns work in very specific circumstances, kept in alignment by the floors which act as supports and dampeners. As the floors begin to pancake they reduced lateral support to the columns and effectively the columns develop kinks from a shockwave, initially they almost ring like a guitar string at some fundamental frequency, then eventually under compressive force they bow like overloaded straws, once bowed even slightly in any direction they have a fraction of the required strength to support even the buildings static mass, let alone the ongoing force of continuing impacts.

But really, in a failure like this, you only test the very weakest component, and in this case it was probably the stays and struts that supported the floors.