Attached below is a stress analysis of girder A2001 which NIST claims had its web was pushed past the edge of its seat at column 79 and the 65,000 lb. load on that end of the girder caused the flange to fail in flexure (fold up and fail due to bending stress). However, the NIST 7 report omitted the 18" high x 3/4" thick stiffeners at the end of the girder which were over the seat. These make the moment of inertia much greater and would prevent the failure.
Frankel drawing 9114 showing the stiffeners is also attached. They were not found until the drawings were released over 3 years after the NIST report. NIST has admitted to omitting them saying in a circular argument fashion that they weren't needed since they were for web crippling and their analysis showed there would be no web crippling. The stiffeners strengthen the flange significantly.