So the footprint of a tower was roughly 208ft x 208ft. The roof was a concrete slab 6 inches thick—likely reinforced with rebar, and of course the large antenna on top. No real way to calculate all of it together, but assuming the concert's density alone was 133 lbs/ft3, then you're looking at about 800 cubic yards of concrete, which would weigh roughly 1600 tons capping off the top of these buildings.
For reference, a fully-loaded 747 weighs 442 tons.
I think the case could be made that 1600 tons sitting at the tippy top is a lot of weight. The support structures designed to hold weight up vertically (and sway with the wind) were compromised at the points of impact by a plane crashing into the building, and the surrounding structure left now had to shoulder not only vertical load but shear load as well. Add fire, molten aluminum, and maybe even wind creating sway to the mix, and I do think you have a situation where taken all together, it was enough to weaken the remaining structure near the plane, and the 1600-ton roof did the rest.
And I will stress this again, I do think 9/11 was an inside job, I just disagree with the premise that it was done via a very elaborate plan involving undercover maintenance crews and slathering thermite gel everywhere.
Even controlled demos aren't perfect
Not all the beams all the way down, no.
So the footprint of a tower was roughly 208ft x 208ft. The roof was a concrete slab 6 inches thick—likely reinforced with rebar, and of course the large antenna on top. No real way to calculate all of it together, but assuming the concert's density alone was 133 lbs/ft3, then you're looking at about 800 cubic yards of concrete, which would weigh roughly 1600 tons capping off the top of these buildings.
For reference, a fully-loaded 747 weighs 442 tons.
I think the case could be made that 1600 tons sitting at the tippy top is a lot of weight. The support structures designed to hold weight up vertically (and sway with the wind) were compromised at the points of impact by a plane crashing into the building, and the surrounding structure left now had to shoulder not only vertical load but shear load as well. Add fire, molten aluminum, and maybe even wind creating sway to the mix, and I do think you have a situation where taken all together, it was enough to weaken the remaining structure near the plane, and the 1600-ton roof did the rest.
And I will stress this again, I do think 9/11 was an inside job, I just disagree with the premise that it was done via a very elaborate plan involving undercover maintenance crews and slathering thermite gel everywhere.