Partin's analysis is certainly interesting. But I have an acquaintance who makes bombs for the military. He told me that he could easily have made a bomb out of the materials McVeigh supposedly used and exploded them in a truck near the building with similar effect. Jayna Davis' book is also interesting, and not even irrelevant if the McVeigh truck story is true, but nothing is certain about what happened in Oklahoma City, except that some FBI guys took the day off to play golf and it helped to resurrect the Clinton Presidency.
McVey’s bomb was incapable of shearing the collumns.
Had there not been all the cutting charges in the basement, the whole thing would have been a job for a small glass company.