There was no free fall. WTC7 took around 18 seconds to come down start to finish.<quoted text>
Funny, when I read the bit about the South Tower damage, I had the same reaction. "Waste Water" doesn't know the material and is just making things up!
I followed the link to the "Structure Magazine" article and found the graphic on the top of page 44 showing "possible damage" from the North Tower, but no mention of South Tower damage. The key word, of course, is "possible," indicating speculation. It is also interesting to see the relative position of the famous column 79 to these areas of damage. The one area of damage that is confirmed is the Southwest corner, about as far from column 79 as you can get! Even the theorized areas of damage do not directly affect column 79.
The story in "Structure Magazine" is very revealing to the careful reader. Again, a look at the top graphic on page 44 shows that column 79 is at the northeast corner of the core columns (in other words, far off-center), and yet the authors (and NIST) speculate that the failure of this single column brought the entire WTC-7 down. I use the word "speculate" because the authors have titled the article "Single Point of Failure: How the loss of one column MAY have led to the collapse of WTC-7"
I emphasize again: "MAY HAVE LED" = speculation
The hypothesized failure of a column far off center, column 79, being responsible for the demise of the entire WTC-7, is a bit of a stretch... and completely without precedent. However, when the symmetric and free-fall drop of the roof are included as conditions that must be met by any theoretical failure sequence, the far-off center single-point failure hypothesis is impossible. But the article mentions neither the period of free fall nor the symmetry of collapse, and this is also telling. These characteristics are readily apparent in any video: