Not to mention the FACT that the columns were 3 stories tall - 36'I'm concerned that we are drifting "off topic" - the thread topic is the unreliability of 9/11 Truther "side" professionals. We are discussing identified flaws with the legitimate professional explanations associated more with the "debunker" side. And clearing up the confused issues can lead to extended debate going further "off-topic". So I will try to keep comments brief - we may need a separate thread or threads.
The Wikipedia article is, in my opinion a good generalised overview. Accurate in most of what it says but does not delve deeply into some details.
But I identify two flaws that are relevant to our current discussion. I wil explain the most blatant one which is in the section addressing Total progressive Collapse.
That explanation is the "Crush Down/Crush Up" hypothesis published by Bazant & Verdure in their 2007 paper "Mechanics of Progressive Collapse: Learning from World Trade Center and Building Demolitions."
I say that explanation is wrong. It has four fatal errors when applied to WTC Tin Towers collapses. And I'm well aware that most debunkers regard Bazant as infallible and that the CD/CU hypothesis is accepted wisdom by many. Here is the outline of my explanatory proof:
1) I believe that B&V fell for the mistake that many debunkers had made by misapplying the "limit case" modelling of the Bazant & Zhou papers of 2001-2. The specific error being the assumption that columns remained inline resisting collapse and were crushed (buckled) as the collapse progressed. And a second associated error - that the collapse started by the "Top Block" dropping so that the upper part of each column impacted on its lower part.
The following are specific examples of false aspects in the quote from Wikipedia:
2) "upper block destroyed the structure below in a progressive series of column failures roughly one story at a time." >> That did NOT happen. The falling debris missed the columns allowing the perimeter columns to fall away and topple and fall away in "sheets" of carious sizes. Not buckled".
3) "Each failure began with the impact of the upper block on the columns of the lower section.." >> Didn't happen. (See #5 below)
4) "This buckled the columns of the story immediately beneath the advancing destruction.." >> Same error - didn't happen that way. Columns were not buckled. Debris fell on floor areas and sheared floors off columns.
5) "This repeated until the upper block reached the ground and the crush-up phase began..." >> Not so - the Top Block was dismantled at the start of progression collapse. (Separate proof available of that assertion.)
The fundamental error is that B&V assumed "columns in line" resisting collapse. The error that B&Z did NOT make 5 years earlier but one that most early truther v debunker discussions got wrong. And was the foundation error of T Szamboti's "Missing Jolt" paper.
I will pause there - members will realise that what I am explaining opposes current "accepted wisdom". And I'm committing "lèse-majesté" - having the unmitigated gall to disagree with Bazant. So I'll await comments. Possibly discussion in another thread?
And I haven't forgotten my earlier reference to "...two flaws that are relevant to our current discussion..". The second flaw can wait.