The 9/11 Forum

http://www.youtube.com/watch?v=20FKED_C ... re=related

I estimate the near corner to have dropped the height of the building in about 5.8 seconds seconds...approximately 16% longer than free fall. I assume a story height of 13 feet...which is conservative.

The NW corner (610' above ground level) of WTC 7 took only about 14% longer than free fall, dropping a much greater height in only about 7 seconds. And it also had much more debris/resistance to deal with.

I've noticed that many many demolitions can't touch WTC 7 in this regard.

Btw look how subtle the cutter charges are in the core area. You wouldn't notice them at all if this building actually had a facade.

It's a concrete structure too.

Well yes, its concrete, which means that it doesn't have the flexural capabilities that steel has. Concrete cracks and crumbles in flexure whereas steel will bend but not break. Thats what makes it all the more ridiculous that tower 7 came down so fast.

A steel frame breaks at the joints... flexing is less likely I would think for an entire structure.