Discussion of “What Did and Did Not Cause Collapse of World Trade Center Twin Towers in New York?” by Zdeněk P. Bažant, Jia-Liang Le, Frank R. Greening, and David B. Benson

摘要

I have read subject article by Bazant et al. with great interest andnwould like to make the following observations:nThere is no need to describe the destruction of WTC1 usingndifferential equations. Simple math plus observations of videosnprove the authors’ model and paper wrong.nThe authors suggests that upper part C u0001of WTC1u0002 drops onnthe lower structure of WTC1—part A—that is, one-way crushednin 97 steps to the ground. During crush of the first tower, thenuppermost story of part A u0001floor 97u0002 formed a layer of debris—npart B—that grows thicker as more stories are crushed by parts Bnand C. What happens using the authors’model is easily calculatednby simple step-by-step calculations. Differential equations are notnreally required!