A 40 MPH Wind Tore This Bridge Apart

On November 7, 1940, the Tacoma Narrows Bridge twisted itself apart in a 42 mph wind — four months after opening. Physics textbooks blamed resonance. They were wrong. The real killer was aeroelastic flutter: the bridge feeding energy to itself, one twist at a time. In this episode of How It Stands, we take apart Galloping Gertie — Leon Moisseiff's record-slender deck, the morning of the collapse minute by minute, the vortex-shedding theory that fails the numbers test, and the self-excited vibration that actually did it. Then: the 1950 rebuild with 33-foot open trusses, the retrofits it forced on bridges across America, and why every long span since is born in a wind tunnel. Chapters: 00:00 Hook — the film everyone knows 00:29 The skinniest bridge (Moisseiff's deflection theory) 02:25 The last morning (November 7, 1940) 03:53 The wrong explanation (the resonance myth) 05:09 The bridge that fed itself (aeroelastic flutter) 06:44 Rebuilding Gertie (the 1950 fix + retrofits) 08:38 The air is not empty (legacy) Sources: WSDOT Tacoma Narrows history (wsdot.wa.gov/TNBhistory), Billah & Scanlan (1991) on the resonance myth, F.B. Farquharson's UW wind-tunnel studies, Historic American Engineering Record (Library of Congress) photo surveys. Real licensed stock footage (Pexels License); no AI-generated visuals. Music: 'Pulsar' by The Grey Room / Density & Time (YouTube Audio Library, no attribution required). #TacomaNarrows #BridgeCollapse #Engineering #GallopingGertie #CivilEngineering #HowItStands CHAPTERS 00:00 HOOK 00:29 CH1 00:54 CH1 01:21 CH1 01:48 CH1 02:25 CH2 02:44 CH2 03:03 CH2 03:24 CH2 03:53 CH3 04:24 CH3 04:52 CH3 05:09 CH4 05:21 CH4 05:53 CH4 06:21 CH4 06:44 CH5 07:03 CH5 07:19 CH5 07:50 CH5 08:18 CH5 08:38 CH6 09:07 CH6 09:24 CH6