Bridge Collapses- More Common Than You Think

The deadly Mississippi River bridge collapse on August 1, 2007 was a tragedy that is not unheard of in the United States. It is the fourth major bridge collapse since 1989.

Recent collapses include:

The "earthquake proof" Cypress Freeway Collapse of October 17, 1989 in which 67 people were injured, declared missing, or killed when a 7.1 magnitude earthquake struck the area.

The Queen Isabella Causeway Disaster -September 15, 2001. Eight people lost their lives due to a multiple barge crash which collapsed the bridge support columns.

The Arkansas River Collapse -May 27, 2002. Fourteen people died as another barge hit a support beam in the state of Oklahoma.

There have been more than 500 failures of bridge structures in the United States since1989 according to a study conducted by the American Society of Civil Engineers. The age of the failed bridges ranged from the construction phase of less than a year to 157 years. The average age of bridges was 52.5 years.

Floods and collisions were the top cause of bridge failures.

Overload and impact forces from vehicles attributed 20% of the total bridge failure.Other causes are design, detailing, construction, material, and maintenance. Human-induced events occurred but were not a major factor.