The Tacoma Narrows Bridge Collapse
The Tacoma Narrows Bridge case shows why an innovative design should not be considered sage merely because it satisfies accepted calculations. The suspension bridge opened in Washington State in July 1940 and quickly became known for its dramatic movement in the wind. On November 7th, only four months after opening, the roadway began twisting violently and eventually collapsed into Puget Sound. Engineers had observed the bridge’s unusual motion, but the causes and potential consequences were not yet fully understood. The central ethical question is whether the bridge should have remained open while its behavior was still being investigated. This case highlights the responsibility to respond cautiously when a new design behaves in ways that models did not predict, especially when the public is exposed to uncertainty. It also demonstrates how a highly visible failure can lead engineers to reconsider the assumptions behind an entire field of design.