<P> Construction on the bridge began in September 1938 . From the time the deck was built, it began to move vertically in windy conditions, which led to construction workers giving the bridge the nickname Galloping Gertie . The motion was observed even when the bridge opened to the public . Several measures aimed at stopping the motion were ineffective, and the bridge's main span finally collapsed under 40 - mile - per - hour (64 km / h) wind conditions the morning of November 7, 1940 . </P> <P> Following the collapse, the United States' involvement in World War II delayed plans to replace the bridge . The portions of the bridge still standing after the collapse, including the towers and cables, were dismantled and sold as scrap metal . Nearly 10 years after the collapse, a new Tacoma Narrows Bridge opened in the same location, using the original bridge's tower pedestals and cable anchorages . The portion of the bridge that fell into the water now serves as an artificial reef . </P> <P> The bridge's collapse had a lasting effect on science and engineering . In many physics textbooks, the event is presented as an example of elementary forced resonance; the bridge collapsed because normal speed winds produced aeroelastic flutter that matched the bridge's natural frequency . The collapse boosted research into bridge aerodynamics - aeroelastics, which has influenced the designs of all later long - span bridges . </P> <Table> <Tr> <Td> </Td> <Td> This section needs additional citations for verification . Please help improve this article by adding citations to reliable sources . Unsourced material may be challenged and removed . (April 2015) (Learn how and when to remove this template message) </Td> </Tr> </Table>

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