9/11 Conspiracies: Fact or Fiction?

[cpk]

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Can you explain how the lower floors, which presumably aren't affected by the fire/heat, could have their angle clips compromised? Is it the shear force coming down on them, and not the weight, coming down on them?

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Right. The forces caused by weight of the building were distributed among the columns. The weight of each floor was borne by the floor joists, which are attached to the columns by the angle clips. The floors themselves did not bear the weight of the floors above--that's borne by the columns. [Sorry if I butchered this--I'm not a physicist or engineer.]

Suddenly, here comes a whole lot of building falling down on to the floor below. This is more than the joists and clips were designed to handle, so they fail. The columns themselves are twisted and distorted by the falling structure. They also fail. (Think also of the I-35W bridge--once the structure failed, the steel began to twist and fracture in spectacular ways.) Each floor adds its weight to the one above and comes crashing in on the floor below.

It wasn't a neat and orderly process, either. Air compressed and expelled from the collapsing floors rushed outwards and also down elevator shafts, blowing out windows several floors below. These explosions of air are passed off by the 9/11 truth squad as squibs from controlled demolitions--even though they are haphazard and apparently random.