Addendum to “Why Did the World Trade Center Collapse?—Simple Analysis”

Abstract

The addendum presents the responses to several questions on a preliminary version (which arrived too late for publication as part of the paper). The questions deal with the aircraft impact at a higher floor of the World Trade Center towers on September 11, 2001 damage to the upper part of the collapsing tower, weakness of connections, plastic cushioning of vertical impact, estimation of the equivalent mass, and the collapse of the adjacent lower building.