this post was submitted on 29 Aug 2025
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Construction began in September 1938. From the time the deck was built, it began to move vertically in windy conditions, so construction workers nicknamed the bridge "Galloping Gertie". The motion continued after the bridge opened to the public, despite several damping measures. The bridge's main span finally collapsed in 40-mile-per-hour (64 km/h) winds on the morning of November 7, 1940, as the deck oscillated in an alternating twisting motion that gradually increased in amplitude until the deck tore apart. The violent swaying and eventual collapse resulted in the death of a cocker spaniel named "Tubby", as well as inflicting injuries on people fleeing the disintegrating bridge or attempting to rescue the stranded dog.

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[–] BackgrndNoize@lemmy.world 19 points 2 weeks ago

the bridge collapsed because moderate winds produced aeroelastic flutter that was self-exciting and unbounded: for any constant sustained wind speed above about 35 mph (56 km/h), the amplitude of the (torsional) flutter oscillation would continuously increase, with a negative damping factor, i.e., a reinforcing effect, opposite to damping.[5] The collapse boosted research into bridge aerodynamics-aeroelastics, which has influenced the designs of all later long-span bridges.