[mpeastend]

Thanks LesPaul, the Chief didn't come out and say it was going to collapse but he said it was too dangerous to fight the fire which, at the time, was solidly across the entire base of the bldg consuming the first 3 or so floors. By the time the bldg came down, it had spread to the 5th & maybe 6th floors.

I shouldn't be even speculating but my opinion is that because the fire was spread across all the footprint of the bldg, weakening the 1st thru 5th floors, when it started coming down it pretty much went straight down. If it had been only on one side of the bldg, wouldn't that make the bldg fall more like a tree that everone seemed to be expecting? Even if that were the case, it probably wouldn't fall like that due to the cross-integrity of the remaining structure because it's all tied together. Red-Beard is right...gravity wants to suck the thing straight down and it requires tremendous force to start it moving otherwise. Trees fall the way they do because their stiffness remains intact along their length and the base was just chopped away. On a bldg, if the bottom structure goes "soft" due to high heat, I don't think the upper structure has the strength like a tree to remain intact and it just seems to collapse on itself as things shear. The loads & forces are tremendous.
Anyway, here I went and started talking about stuff I know nothing about. Now we just need Rosie to come and talk about steel burning.