Global Analysis of World Trade Center Towers
New York, NY
The collapse of the World Trade Center (WTC) towers on 11 September 2001 was an unprecedented event in U.S. history. NIST retained SGH and ARA to develop computer simulations of the structural response of WTC 1 and 2 to aircraft impact and subsequent fires, and of WTC 7 to damage from impact of falling debris from WTC 1 and 2 and the subsequent fires at various points during the collapse. ARA performed the aircraft impact analyses and SGH determined the structural response of the damaged towers to subsequent fires. We compared the model results with observations of the collapse process captured in photographs and videos and used the information learned from the study to better understand the behavior of tall steel buildings.