Tacoma Narrows Bridge Collapse Timeline
About This Timeline
This interactive timeline chronicles the dramatic events of November 7, 1940, when wind-induced resonance caused the catastrophic collapse of the Tacoma Narrows Bridge - one of the most famous engineering failures in history.
The Physics of the Collapse
What Caused the Oscillations?
- Vortex shedding: Wind flowing past the bridge deck created alternating vortices
- Periodic forcing: These vortices applied periodic forces to the structure
- Natural frequency match: The forcing frequency matched the bridge's natural frequency
Why Did It Get Worse?
- Initial vertical oscillations had moderate damping
- System shifted to torsional (twisting) mode
- Torsional mode had much less damping
- Amplitude grew until structural failure
Key Facts
| Parameter | Value |
|---|---|
| Bridge opened | July 1, 1940 |
| Span length | 2,800 feet (853 m) |
| Wind speed at collapse | 35-40 mph |
| Maximum twist angle | 45° |
| Torsional amplitude | 28 feet |
| Time to collapse | ~4 hours |
| Casualties | None (1 dog) |
Legacy
The Tacoma Narrows collapse revolutionized bridge engineering:
- Led to wind tunnel testing of bridge designs
- Introduced aerodynamic considerations in bridge design
- Improved understanding of structural resonance
- Modern bridges use damping and streamlined shapes
Lesson Plan
Discussion Questions
- Why was the bridge nicknamed "Galloping Gertie" before it collapsed?
- How could engineers have prevented this disaster?
- What other structures might be vulnerable to wind-induced resonance?