[MHGinTN]

The towers were mostly turned to dust. When the rubble pile is examined that afternoon, before Bldg 7 came down, the rubble was less than the remains of the eight story building six, as revealed in photgraphs made that day before #7 came down.

[TXnMA]

"The towers were mostly turned to dust."

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Not so -- but there was an impressive volume of drywall dust..

The WTC towers were mostly steel -- and empty space. (Otherwise they would not have been functional...) Therefore, the ratio of the volume of compacted concrete debris to building volume was surprisingly small. Also, much of the debris wound up in the basement[s] -- leaving a deceptively small apparent aboveground rubble pile.

I saw little evidence of compressive failure of concrete in the WTC towers. (Concrete reverted to cement dust and shattered aggregate -- the "hallmark" of high-VOD demolition charge - controlled demolition...)

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Heat-softened/weakened steel + barely-adequate floor connectors + vertically-guiding core and columns + gravity = vertical pancake collapse (with lateral smoke/debris "puffs" as each floor volume was compacted...
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FYI, that is distinctly unlike what I saw across ~18"-24" spans -- at 40-foot intervals -- of the single, huge 200 ft long, 5 ft high, 3 ft thick "Main Spandrel" or "Header Beam" spanning the Murrah Building at third floor level:

TXnMA -- ca AD 2000

BUT, FRiend, Building collapse mechanisms are not the subject of this thread -- and are a distraction from its "Qdrop analysis" mission.

If you want to continue to beat the dead horse of WTC building collapse, please do it elsewhere. Start your own thread, and -- if you want to face scientific facts -- ping me to it...

(See my FRProfile for my "Creds" re this matter...)

FRegards,
TXnMA