Progressive Collapse of the World Trade Center: Simple Analysis

Abstract

The collapse behavior of the World Trade Center towers is considered formally as a propagating instability phenomenon. The application of associated concepts enables the residual capacities of both towers after the onset of collapse to be formally estimated. This information is combined into a simplified variable-mass collapse model of the overall dynamical behavior. The resulting, nonlinear governing equation of motion can be solved in closed form, to yield compact information about the overall collapse conditions.