Construction of the original Tacoma Narrows Bridge, which opened in July 1940. (Photos courtesy of Washington State Archives)

This is Washington’s tale of two bridges. Opening just one day apart in July 1940, 75 years ago, the Tacoma Narrows Bridge and the Lake Washington Floating Bridge both galvanized human movement and economic prosperity in Washington state. They foreshadowed the developing prowess of Washington. However, this growth was not without its pains.

Both bridges were engineering marvels. The Tacoma Narrows Bridge, connecting Tacoma and the Kitsap Peninsula, was the third-longest suspension bridge in the world, while the Lake Washington Floating Bridge, which linked Seattle and Mercer Island, was the largest floating structure in the world. Although both were miraculous feats of engineering, they were at the mercy of the elements. When man’s engineering is pitted against the power of nature, nature is often the victor.

 

Water-level view of Lake Washington Floating Bridge.

The Tacoma Narrows Bridge, with its graceful and web-like frame, had a tendency to buck like a rodeo bronco whenever strong winds blew off the Sound. Eventually, structural instability caused it to crash down one windy and momentous day, Nov.  7, 1940, only four months after its opening, luckily without any loss of human life. As for the more stable Mercer Island Bridge, human error was partly to blame for its destruction. During repairs in November 1990, workers left open the hatches of the mammoth concrete pontoons that kept the bridge afloat. Consequentially, the pontoons filled with water during a large storm, causing the bridge to sink into Lake Washington.

Learning from their past mistakes, engineers fixed flaws and rebuilt both bridges with sound structural integrity. Both remain operational to this day.

The Washington State Archives holds many documents documents and images from these monumental bridge openings. In addition, this July marks the centennial of the Sunset Highway, the state’s first passable route through the Cascade Mountains at Snoqualmie Pass.