Why the NIST WTC Report on the Towers is False
by Kevin Ryan
This article first appeared at ReThink911.org.
The official account of the Twin Towers’ destruction was produced by the National Institute of Standards and Technology (NIST) and released in September of 2005. Unfortunately, NIST’s report only provided a hypothesis of the events leading up to the initiation of the collapses, or the “collapse initiation sequence.” NIST did not attempt to explain how once the collapses initiated, the upper sections of these 110-story skyscrapers would continue falling downward through the path of greatest resistance, instead simply asserting that, once each building was destabilized, “global collapse ensued.” However, we can examine the general features of NIST’s collapse initiation sequence for both Twin Towers to see if it is consistent with known facts, or is at least self-consistent.
The seven steps of NIST’s collapse initiation sequence that are common to both Twin Towers are as follows:
1. A number of columns were severed by aircraft impact
2. Loads were redistributed to the remaining columns
3. Fireproofing was “widely dislodged”
4. Columns and floor assemblies were softened by high temperatures
5. Softened floor assemblies began to sag
6. Sagging floors pulled the exterior columns inward, causing columns to buckle
7. Instability spread around the exterior of the building
The first two steps of this sequence are not surprising. With regard to step one, we can accept that approximately 15% of the columns were severed in each building by aircraft impact. This is quite low compared to original design claims reported in the mid-1960s by the Engineering News-Record that said the towers could lose more than 25% of their columns without having any problems. As for the second step, NIST says the loads actually decreased on some columns and increased slightly for others. Again, there is no problem here considering similar design claims that the exterior columns could withstand 2,000% increases in live load.
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