I think it is a very good paper! Of course it only analyses the first 3.17 seconds of the displacement of the WTC1 roof line and the upper part below down to floor 98, BUT we can learn a lot from that.
During these 3.17 seconds the roof line displaces say 33 metres downwards ... but nothing happens to the structure below floor 93!
Strange, isn't it. When the roof line has dropped 33 meters, evidently 33 meters of structure below floor 93 should have been completely crushed down then by the rigid upper part crushing down.
BUT - the structure below floor 93 remains undamaged!
What you see instead is the upper part - floor 98 to the roof - being compressed or imploding during these 3.17 seconds.
I have described it before at
http://heiwaco.tripod.com/nist3.htm ... and no JREF member has managed to debunk my observations there.
The paper under discussion does not analyse what happens after the 3.17 seconds. The paper assumes that the upper part columns actually contact the lower structure columns during these 3.17 seconds, BUT, as soon as the the columns have sheared off (or whatever), the two ends of all columns never meet again.
The upper part columns should then start to punch holes in the floors below or just hit air outside the structure below AND the lower structure columns should start to punch holes in the upper part floors.
It is like a collision of two ships! Both ships are damaged, and after a while the local destruction is arrested, etc.
NIST assumes of course that the upper part of WTC1 remains completely undamaged during the whole collapse and applies its PE on the lower structure that lacks SE, etc. BUT it is just silly nonsense.
Reason for NIST staff suggesting such nonsense is that if anybody does not do it, he or she is a terrorist according to president GWB. We will see if things change after 20 January!
. So I'm not going to be addressing any further points until much later. 
), there are some engineering, architectural, or just plain trained-better-in-physics-than-most-people types hanging around here. And I personally find it telling that they're dismissing the paper; Dave Rogers in particular is highlighting a very basic problem that by itself invalidates the conclusions. To me, who's not educated in engineering or architectural concepts, and who's physics only extends to the required courses level in college, this paper still smells fishy, just for the things I've objected to so far. And that's even before taking into account Dave Rogers post. Combining my own personal sense that something feels wrong with the utter dismissal by other trained types here may not add up to a full refutation, but it does indicate that there are very core problems with the paper. Others can elucidate those core issues later, and with better clarity than I. For now, this layman's read of the paper is setting off alarm bells.
