9/11 - WTC/Pentagon/Shanksville m.m - Tråd Nr 2

Shear Stud Failure: A third case of fabrication involves shear studs again – this time the shear studs that connected to the steel beams to the floor slab.

NIST claims that, due to the failure of that crucial girder discussed earlier, the floor beams were able to expand without constraint. But each of these beams was connected to the floor slab by 28 high-strength shear studs. These studs should have provided plenty of restraint.

They would have, except for the fact, NIST tells us, that they all broke.

Why did they break? Because of what NIST calls “differential thermal expansion,” which is simply a technical way of saying that, in response to the heat from the fires, the steel beams expanded more than the floor slabs did.

But why would that have been the case? Steel and concrete have virtually the same “coefficient of thermal expansion,” meaning that they expand virtually the same amount in response to heat. If that were not the case, reinforced concrete – that is, concrete reinforced with steel – would break up when the weather got very hot or very cold. NIST itself points out that “steel and concrete have similar coefficients of thermal expansion.”

So why does NIST claim that the shear studs broke because of differential thermal expansion?

To understand this point, you need to understand that NIST’s theory is an almost totally computer-based theory. NIST fed various variables into a computer program, which then supposedly told it how WTC 7 would have reacted to its fires. So, what did NIST feed into its computer that caused it to say that the steel would have expanded so much more than the concrete slab that all of the shear studs would have broken? The answer is given in this bland statement:

No thermal expansion or material degradation was considered for the concrete slab, as the slab was not heated in this analysis.

When I first read this statement, I had to rub my eyes. Surely, I thought, I have mis-read the statement, because a few pages earlier, NIST had said: “differential thermal expansion occurred between the steel floor beams and concrete slab when the composite floor was subjected to fire.” The “composite floor,” by definition, is the steel beams made composite with the floor slab by means of the shear studs. So NIST had clearly said, in stating that the composite floor had been subjected to fire, that both the steel beams and the concrete slab had been heated.

But then in the eye-rubbing passage, NIST said: When doing its computer simulation, it told the computer that only the steel beams had been heated; the concrete floor slab was not. [54]

So of course the steel beams would have expanded, while the floor slabs stayed stationary, thereby causing the sheer studs to break, after which the steel beams could expand like crazy and bump into Column 79, which then causes the whole building to come down.

A comic book version of the official story of 9/11 has been published. [55] This was an exercise in redundancy, because the official reports already are the comic book version of what happened on 9/11. In any case, I come now to NIST’s miracle.
http://www.globalresearch.ca/the-mysterious-collapse-of-wtc-seven/15201