ThERat said:
this sounds exactly like the official version. However, from the video I understand that
1. the support for the Twin Towers came from 47 steel beams in the center of the building.
2. the temperature wasn't high enough to melt the steel beams
3. the pancake theory can not explain the free fall collapse
4. the 47 steel beams could not have collapsed like this, at least they should have still stuck out
5. why did the building next to it collapse the same way (a 47-storey building with fires at only 2 floors)
whatever it was, the official version does not convince me at all. The civil engineers in this forum could maybe enlighten me. It's the scientific explanations that are intruiging.
1. "Rather than a typical frame building curtained in stone or glass, it was in essence a giant steel lattice, acting almost like a bearing wall structure: that is, it was held up mostly by the closely spaced exterior columns, which, together with their cross members, formed a right-square, or Vierendeel-type truss." ~Robert Stern's New York 1960.
2. As mentioned before, the impact blew off the fireproofing. Specifically, steel in buildings is generally coated with, IIRC, zinc, which enamels it all around. This, however, is not actually structurally integrated as part of the metal, and the impact from the airplanes was actually sufficient enough to blow off the zinc coating.
3. Why not? It is a chain reaction effect. As one floor collapses on another, the floor beneath loses integrity as the weight is suddenly jarring it, while the ones on top are jarred by every impact in turn. Steel beams are not designed to have thousands of tons of metal falling against them.
4. The steel beams were not continuous structures, there are many of them. Therefore, they broke up, and landed in the scattered mess at "Ground Zero" as shown in all those pictures.
5. My guess is impact from debries off of the World Trade Center--notice how they threw off tonnes of material as they went down--and even more so seismic tremors, as 100 story buildings smashing into the ground is probably going to do some damage to the topsoil.
Furthermore, if it was all engineered, then why did they bother to blow up a puny office building that wasn't even part of the main complex as well? It's like saying "Well, since we blew up the Empire State Building, might as well blow up the rest of the buildings around it, too. Nah, actually, we'll just blow up one". Since I don't think that it would make much of an impact (pardon the pun), I doubt that the collapse of the 47 story building was anything other than a sideeffect of the main collapses.