The truther experts appear to disregard the details/mechanism which enables heat to cause a steel frame to fail.... which of course would only initiate a (runaway) progression of non heat related failures. So truthers will claim there was in adequate heat to destroy the frame in part and make the false claim there was melted steel indicating the heat destruction was not from jet fuel or office fires.Some good points Jeffrey. These three the most important in my opinion:
<< My personal special focus as you know. BUT it only works if the "layman" is interested in learning and is prepared to read, follow and discuss the steps of explanation. Very few are. (Do you remember "Jango"?)
<< Which poses a special challenge for many engineering or applied physics specialists. It makes argument in generic qualified (descriptive) form the necessary method. And most engineers are left brain details focused. They are not comfortable arguing without precise numbers and specific structural details.
<< To adequately explain Twin Towers collapses needs understanding of four distinct stages - each with a different mechanism. Very few persons attempting to provide explanations even recognise the two main stages of "initiation" and "progression". And, consequently, they get confused when they conflate different stages.
My sense is not enough attention was given to the importance of the"progression" of failures and how these escalated, spread through the structure and were "unstoppable" and led to total collapse. So yeah... it would be a educated guess at best at how loads were redistributed to other columns beams and so on which exceeded their capacity. Load "redistribution" for sure is not an intuitive concept. How does that work? Without this there would have been no collapse. Has any expert drilled down into this? We know NIST punted and said.... an "global collapse ensued" or words to that effect. Oh goodie... I get it NIST!
Load distribution... or the "frame managing the loads is also key and mysterious. There was obviously no new loads and the structures were not operating at the limit of their load bearing capacity... But somehow... the loads which didn't grow in size were able to wreck the frame and cause the collapse. Just how does that happen? And how does "residual capacity" come in to play.... was there enough? (obviously not)....how is it determined and what where should that residual capacity applied?
How would a local failure be "arrested" and confined and not "domino" to other regions of the structure. Was this "anti domino" something engineers consider? If so what were they in these structures? What are other anti domino strategies used in other high rise designs....
Engineers... speak out!
YES there were stages with different mechanisms dominating or defining them... YES there were periods of transitions from one stage to another. It seems "obvious" but also not explained at all in my opinion. The "explosion" notion is easy to grasp even when not detailed... everyone knows explosions destroy things.