Still speaking of bridges (from last week), the demise on November 7,  1940, of the Tacoma Narrows Bridge was a “spectacular” collapse. Likely few of us were witness to this event but via the TV news we knew.

Construction began in September 1938. So the bridge was only four months old but from the time the deck was built, it began to move vertically in windy conditions and workers nicknamed it Galloping Gertie. Remedial efforts were made but to no avail. 

The bridge’s main span finally collapsed in the 40-MPH winds on that morning, as “the deck oscillated in an alternating twisting motion and gradually increased in amplitude until the deck tore apart.” 

The only fatality was a cocker spaniel named Tubby but people trying to rescue the dog or flee the bridge did sustain injuries.

Efforts to replace the bridge were delayed by U.S. involvement in World War II as well as engineering and finance issues. But in 1950, a new Tacoma Narrows Bridge opened in the same location. 

Why did Gertie Gallop? “Because planners expected fairly light traffic, the bridge was designed with two lanes and was only 39 feet wide. This was quite narrow, especially in comparison with its length of nearly 6000-feet (the third-longest suspension bridge in the world at the time).” The roadway plate girders were also shallow, another detrimental factor.

You can watch on YouTube a newsreel taken on the day of the collapse. It is a sobering sight. 

Source: Wikipedia