An Email Conversation with Steven Jones
Our buddy LDS Patriot has a series of posts from an RW Cronk on his email correspondence with Steven Jones, formerly of BYU. Quoting from Mr Cronk's initial email:
In my view, this combines some heavy architecture with physics. The missing link that you did not mention in your presentation is item #3 in the above list. The key architectural pieces involved are trusses 1 and 2. The architecture of floors 5 through 7 was unique because they had a transfer system between floors 5 and 7 that included the two trusses that are at the core of the collapse. This system of cantilever girders and trusses was supposed to be a kind of converter of loads between the Con-Edison substation (that WTC 7 was built on top of) and WTC 7 itself. The two buildings had different architectures and so there needed to be a conversion point between the two. The debris impacted and damaged components adjacent to truss #2. If trusses 1 and 2 failed, they would pull the whole line of columns over simultaneously since they were all attached in the middle of that transfer area between floors 5 and 7.
As you can see, Mr Cronk has done his homework. Terrific reading, highly recommended