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Politics : Foreign Affairs Discussion Group -- Ignore unavailable to you. Want to Upgrade?

To: Orcastraiter who wrote (175274)	11/18/2005 4:47:07 PM
From: neolib	Read Replies (1) \| Respond to of 281500

The problem lies in being able to answer why the buildings collapsed in near free fall time. Progressive collapses, as put forth by NIST and FEMA for all three buildings, do not address the conservation of momentum issues and the symmetry of collapse. Well, a CE friend of mine sent me a fairly detailed engineering analysis that made sense to me. Its been a few years ago. But the basics are simple. The two main towers consisted of structural columns in the center ringing the elevator shafts, plus the exterior surface of the building which was sizeable steel. The planes had a large fuel load on impact, (100,000 lbs+ IIRC). This fuel burned down the interior elevator shaft region, weakening the central steel. The collapse was from the center, which is why the thing fell largely within the building footprint. No, magic involved. Just like has happened after the Northridge earthquake in CA, or some of the Hurricanes in Florida, the building code and engineering societies have revamped codes due to 9/11. Engineers don't in fact anticipate everything, and safety codes keep evolving based on what actually happens.