1. Engineering Disasters: World Trade Center Collapse
Tom Rebold

2. Some Recent Engineering Disasters
Cosco Busan ,000 gal oil
New Orleans Levy Breach 700 deaths
Minneapolis Bridge deaths
Mars Polar Lander $120 million
Any others?

3. Why do we have disasters?

4. Progress and Failure

8. NIST Report
The study has determined, based on photographs, that perimeter columns bowed inward on One WTC’s south face and Two WTC’s east face, “some” minutes prior to collapse. “Initiation of global collapse was first observed by the tilting of building sections above the impact regions” of both towers, says the report. One WTC tilted to the south and Two WTC tilted to the east and south and twisted in a counterclockwise motion.

10. WTC Steel Truss Burn Experiment