Why the Tacoma Narrows Bridge Really Fell (It Wasn't Resonance)

On November 7th, 1940, the Tacoma Narrows Bridge twisted itself apart in a 42 mph wind, four months after opening. Every physics textbook says it was resonance. It wasn't. In this video we follow the load path of "Galloping Gertie" from the wind to the water: deflection theory, why Moisseiff's 8-foot plate girders were a mistake, why vortex shedding can't explain a 0.2 Hz twist, what aeroelastic flutter actually is, and how an aerodynamicist from Caltech changed bridge engineering forever. Chapters 0:00 A bridge that twisted itself to death 0:42 Part 1 - A bridge too beautiful 3:01 Part 2 - Why resonance doesn't explain it 4:32 Part 3 - What really happened: flutter 7:16 Part 4 - The load path 9:33 What Gertie taught every engineer since Sources Washington State DOT, Tacoma Narrows Bridge history: https://wsdot.wa.gov/ Billah, K. Y. & Scanlan, R. H. (1991), "Resonance, Tacoma Narrows bridge failure, and undergraduate physics textbooks", American Journal of Physics 59(2), 118-124 Ammann, O. H., von Kármán, T. & Woodruff, G. B. (1941), "The Failure of the Tacoma Narrows Bridge", Federal Works Agency Farquharson, F. B. (1949-54), "Aerodynamic Stability of Suspension Bridges", University of Washington Some illustrations in this video were generated with AI tools and are labelled as such. Narration voice: synthetic (ElevenLabs), script written and checked by me. Music and sound design: original. Load Path - how things hold, move and fail. New engineering explainers every week.