The Tacoma Narrows Bridge, also known as "Galloping Gertie," was a suspension bridge that spanned the Tacoma Narrows strait of Puget Sound in Washington State. It opened to traffic on July 1, 1940, but tragically collapsed just four months later, on November 7, 1940. The collapse was caused by aeroelastic flutter, a phenomenon where wind-induced vibrations led to the bridge's failure. The bridge's design, which was intended to be flexible, did not adequately account for aerodynamic forces, resulting in violent oscillations that ultimately tore the bridge apart. The collapse was captured on film and has since become a classic case study in engineering and physics.
The disaster led to significant advancements in bridge design, emphasizing the importance of considering wind effects in suspension bridges. After the collapse of the original, a replacement bridge was constructed and opened on October 14, 1950, incorporating lessons learned from the collapse. This new bridge, often referred to as "Sturdy Gertie," was designed with a deeper and wider deck truss to address the aerodynamic stability issues that led to the collapse of the original bridge. It successfully carried traffic for over 40 years until population growth and increased traffic necessitated the construction of a second span.
Construction of the second Tacoma Narrows Bridge began in 2002 and was completed in 2007. This new bridge, located parallel to the 1950 bridge, features a main span of 2,800 feet and provides three lanes of eastbound traffic, along with shoulders and a separated bike/pedestrian path. The two bridges together form a vital transportation link between Tacoma and the Kitsap Peninsula, significantly improving traffic flow and reducing congestion.
