Reply #20: and my structural engineers are better than yours...

[LARED]

Huh? Speaking of making stuff up

The link you provided is a paper written by Agricultural Engineers not Structural engineers.

Did you think no one would notice the difference?

And even if the floors buckle and allow movement of the core relative to the outer columns there is no explanation for the core columns telescoping on their own lengths.

I think there is a pretty reasonable explianation. Column strength is very dependent of lateral support. In the WTC some of that lateral support came from the floor trusses for the core and most of the lateral support for the outer column came from the floor joists. Also keep in mind that once the outer columns cease to provide support, (ie the top section starts to topple) the other column must take up the additional load. Also as the core starts to rotate it has now been put in a stress condition it was not designed to handle.

The compressive forces on the columns actually lessen once they start to tilt, if only a little,

How does that happen?

so why is it exactly at that moment that every column in the top begins to telescope like a folding pointer?

What video are you looking at? The top section comes apart from the bottom of it, to the top. As the bottom floors come apart the sections above them lose all structural integrity.