Lessons Learned on Improving Resistance of Buildings to Terrorist Attacks

Abstract

This paper presents some findings of the FEMA and SEI/ASCE sponsored studies of structural performance of New York’s World Trade Center (WTC) following the attacks of September 11, 2001, and the Murrah Building following the April 19, 1995, Oklahoma City bombing. The WTC collapses were caused not by aircraft impact alone but by the combination of impact and the resulting fire that weakened structural members and connections. On the other hand, the Murrah Building collapsed as a direct result of the blast. Although these studies call for further research in a number of areas, this report summarizes some of the lessons learned.