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["David Sharp" <Ausgang(--nospam--at)e46fanatics.com>]

I too would like to pipe in supporting the comments of Charlie Carter. 

 

I was the 'fastener guy' on the SEAoNY WTC team, and it seems clear to me that some unfortunate comments were made in the NOVA special.  Now more than ever, I understand why the NTSB keeps their mouths shut after aircraft accidents until all the evidence is thoroughly examined.

 

It seems that a few people forgot that we are still at the PRELIMINARY stages of what will be learned.  NIST is still in the process of receiving and cataloging our (SEAoNY's) steel pieces.  We continue to find useful pieces for study to this day, and there still are barges waiting to be unloaded at the scrapyard.

 

I found the strongest parts of the NOVA special to be the explanations of the theories behind the mechanisms of failure.  It remains to be seen which theories are born out and validated by the analysis just getting under way at NIST.  I am very encouraged by the thoughtful, deliberative approach being taken by Dr. Gross and his colleagues at NIST's Building & Fire Research Laboratory.

 

Personally, I found there to be too much simplification in the NOVA program.  For example, it was stated that ALL of the floor trusses were attached at the core and ran to the perimeter columns.  Obviously, this couldn't be true for the corners --- which relied on more traditional beams.

 

Another example was when it was stated that the aircraft was 'made of aluminum' ---- perhaps to suggest it was light and fragile.  Who knows.  But, would an aeronautical engineer suggest that a wing spar is anything other than a robust structure?  NOVA treated the landing gear and engines as if they are the only parts that need to be treated as 'solid' projectiles.  Whereas, something as seemingly mundane as a set of golfclubs in the baggage hold could likely do some nasty things to whatever they struck at the velocities being quoted.

 

Yet another glaring example was when Dr. Barnett was quoted about the 'first steel building (he ever heard of) to collapse from fire'.  He was talking about WTC 7, not the twin towers.  The engineering for that building wasn't even done by Les Robertson or his colleagues at Skillings, but by Cantor's office.   Anyone who reads the FEMA report ought not skip the chapter on WTC 7.  Credit is due Ramon Gilsanz for not letting us all focus too exclusively on WTC 1 and 2, when there was much to be learned from WTC 4, 5, and 7.

 

The simplification of the graphics depicting the floor trusses was disappointing as well.  Modeling the system without the floor slab and showing the trusses dropping as independent units is misleading.

 

I've rattled on long enough, so I'll conclude with this:  Who among us would confidently today state that we could design a tall office building capable of withstanding whatever type of terrorist attack may be possible 30 some years from today? 

 

Yet, THAT is what some people seem to have expected from Les Robertson in 1968,

 

though they can't count me among them,

 

David Sharp

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