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mhgaffney · 07-16-2009, 06:53 PM

As for the perimeter wall -- NIST studied a representative perimeter column from WTC one (Column 151 between the 93rd and 99th floors)

The demand capacity ratio of this column was .18 -- which gives a factor of safety of 5.7 --

This column could support almost 6 times the anticipated load -- before showing any signs of damage.

For a diagram of this column see Fig 4.34 and 4.35 on page 101

http://wtc.nist.gov/pubs/NISTNCSTAR1-2Draft.pdf

You will find a discussion of demand/capacity ratios starting on page # 65. In retrospect it is a pathetic discussion. NIST seems to make a big deal of the fact that many of the steel components -- cross beams etc -- had a demand capacity ration of less than 1.0

It's garbage science since the function of these other elements was simply to tie together the columns -- which bore the weight.

NIST confirmed to me a=in an email that the representative perimeter column did have a factor of safety of 5.7. The number is correct - though NIST doesn't mention it in the report. At least, not that I can find.

I can guess why they did not mention it. A whopping 5.7 factor of safety blows to hell the official story.

07-16-2009, 06:53 PM	#25
mhgaffney Ring of Famer Join Date: Apr 2006 Posts: 9,845	As for the perimeter wall -- NIST studied a representative perimeter column from WTC one (Column 151 between the 93rd and 99th floors) The demand capacity ratio of this column was .18 -- which gives a factor of safety of 5.7 -- This column could support almost 6 times the anticipated load -- before showing any signs of damage. For a diagram of this column see Fig 4.34 and 4.35 on page 101 http://wtc.nist.gov/pubs/NISTNCSTAR1-2Draft.pdf You will find a discussion of demand/capacity ratios starting on page # 65. In retrospect it is a pathetic discussion. NIST seems to make a big deal of the fact that many of the steel components -- cross beams etc -- had a demand capacity ration of less than 1.0 It's garbage science since the function of these other elements was simply to tie together the columns -- which bore the weight. NIST confirmed to me a=in an email that the representative perimeter column did have a factor of safety of 5.7. The number is correct - though NIST doesn't mention it in the report. At least, not that I can find. I can guess why they did not mention it. A whopping 5.7 factor of safety blows to hell the official story.