OK, I would like somebody to answer 2 questions-
1, What was the height of the rubble at ground zero immediately after the towers collapsed?
2, as the pile of rubble was very much lower than the original height of the quarter mille high towers, what turned the remainder to dust? even steel dust, and does the NIST explanation of a simple pancake collapse really provide the answer?
Each tower was 110 stories and 415 meters high above ground and had 6 or 7 (from memory)
basement levels below ground, which I estimate to be 25 meters deep, giving the towers a total hight from lowest basement level of 440m.
The
towers consisted of 95% air and 5% building materials (composite floors, steel columns, cladding...). Thus, if they collapse and are fully compacted (all air removed), they'd shrink to 440m * 5% = 22m. However, that is not realistic, there will always be air trapped, so
let's allow for half of the debris pile to consist of air. Towers would shrink to 44m above lowest basement level, if they remained entirely within the 63m x 63m footprint.
25 of those 44m go into the basement level underground. Above ground, we have to account for only the remaining 19m worth of debris tower.
That debris above ground spreads out to the sides. Let's
assume that it formed a pyramid with a base length that's three times the width of the tower, or a base area that is nine times the footprint area.
The volume of a pyramid can be calculated by the formula
Vpyr = 1/3 Bpyr*hpyr where B is the base area and h the height.
This volume would be equal to the volume of our 19m debris tower, whose Base are B
tower = 1/9 B
pyr and whose volume is
Vtower = Btower * 19m = 1/9 Bpyr * 19m
With
Vpyr = Vtower
We get
1/3 Bpyr*hpyr = 1/9 Bpyr * 19m | *3
<=> Bpyr*hpyr = 1/3 Bpyr * 19m | / Bpyr
<=> hpyr = 1/3 * 19m = 6.333 meters
So in theory, we expect the debris pile to be only a little higher than an average man, because most of the towers is air, most of the debris goes into the basement, and the rest spills to the sides.
If anything is strange here it's the fact that the debris piles were higher than this expectation.
I guess it is because so
little of them turned to dust.
ETA: I formatted in blue the assumptions that went into my calculation. Feel free to change or correct those assumptions if you don't like them.