By Donald Dusenberry, on September 8, 2021
Members of the profession study such tragic events to try and ensure that something similar won’t happen again
The events of 9/11 shook the world.
Before that day, we could not imagine that someone would be bold and cruel enough to enact such violence. We could not imagine that two iconic 110-story skyscrapers would collapse in the middle of a U.S. city, gouging and crushing other buildings for hundreds of feet in all directions.
We asked ourselves, “How could this possibly happen? How could they collapse?” These are natural questions that express the scope of the loss we felt on that day.
Structural engineers asked these questions, too, but they also asked the contrasting question: How did the World Trade Center towers manage to stand up to the attack at all, even for a short while? The damage was extensive. Commercial aircraft flying at nearly top speed crashed into the buildings, cutting wide swaths through the exterior walls and inflicting extensive interior damage. Shouldn’t that have been enough to cause immediate collapse?