North Tower Acceleration

[William Seger]

155. This was discussed extensively on the JREF forum

Since I can easily predict your knee-jerk reaction to posting links to that site, I'm not much inclined to waste time digging them up -- go find it, if you're really interested. But anyway, Ross' paper itself is the only source necessary to prove that it includes both energy losses from pulverizing concrete and energy lost due to the inelastic collision, as if they were two different things. Remove that double-counting, and Ross' claimed energy deficiency disappears.

And Bazant's observation about the maximum force a column can transmit to the structure below was not a response to Ross' paper; it was part of his response to a Discussion (a letter to the editor) concerning his last paper published in the ASCE Journal of Engineering Mechanics. Since Ross apparently never made any attempt to get his paper published in a peer-reviewed journal, Bazant has never had any reason to pay any attention to it, but his observation nonetheless pulls the rug out from under Ross' momentum transfer analysis by exposing a fatal assumption.