Hulsey's work here is basically a version of
@gerrycan, et al, from 2013. At that time similar arguments were made in this extensive thread.
https://www.metabunk.org/critical-errors-and-omissions-in-wtc7-report-uncovered.t2332/
I repeat two posts below that I think are still relevant.
(Note I refer to G79-44, which is the girder between columns 79 and 44, i.e. A2001
https://www.metabunk.org/posts/69718/
The turning point for me was viewing this video
Source: https://www.youtube.com/watch?v=VQkylMIuH-g
It shows that G79-44 (in green) did not trigger anything, and in fact the video starts at the point where the floor above it has fallen onto it, and the girder is in place, just buckled or bowed.
I though "that's very odd, I thought that the girder falling was the initiating event". So I decided to read 1-9-Structural again, and I realized that they did not. It's been a huge misrepresentation. Sure they describe it as failed, but they also describe a lot of other girder and beams as failed, including the matching girder to the south, which failed around 30 minutes earlier:
(not to mention all the beams that had "loss of vertical support")
At which point I realized this entire argument about the stiffener plates has no significant impact on NISTs description of what happened.
https://www.metabunk.org/posts/69718/
Here's what I think happened, and I admit from the start it sounds a little silly, but that's only because it accounts for human failings in paraphrasing and reducing a description of huge complexity.
- NCSTAR 1-9 "Structural Fire Response and Probable Collapse Sequence of World Trade Center Building 7" is the comprehensive report on the collapse
- NCSTAR 1-A "Final Report on the collapse of WTC7" is essentially a summary of this and other reports.
1-A-Final sums up about 100 pages of 1-9-Structural with a couple of paragraphs:
External Quote:
Fire-induced thermal expansion of the floor system surrounding Column 79 led to the collapse of
Floor 13, which triggered a cascade of floor failures. In this case, the floor beams on the east side of the
building expanded enough that they pushed the girder spanning between Columns 79 and 44 to the west
on the 13th floor. (See Figure 1–5 for column numbering and the locations of girders and beams.) This
movement was enough for the girder to walk off of its support at Column 79.
The unsupported girder and other local fire-induced damage caused Floor 13 to collapse, beginning a
cascade of floor failures down to the 5th floor (which, as noted in Section 1.2.3, was much thicker and
stronger). Many of these floors had already been at least partially weakened by the fires in the vicinity of
Column 79. This left Column 79 with insufficient lateral support, and as a consequence, the column
buckled eastward, becoming the initial local failure for collapse initiation.
This summation of 1-A-Final give undue weight to the effects the 79-44 girder, giving the impression that the girder actually fell, and made the floors below it collapse. Hence the importance people place on how far it was pushed.
In fact the simulation
and the information in 1-9-Structural show that the girder
did not initially fall. What fell were the beams and girders affected by "other fire-induced local damage". Including on the floor ABOVE the girder.
The 79-44 girder was again given undue focus in the NIST WTC7 Tech Briefing. But again they did not say the girder fell. They did not say the falling girder triggered the collapse.
https://www.metabunk.org/files/NIST_WTC7_Tech_Briefing.pdf
And the actual technical briefing was very simplistic, and not very good.
So when we discuss what "NIST claims", we should look at their detailed claims, not the summary, and not a slideshow.