Across the shimmering waters of Lake Washington stretches the Homer M. Hadley Memorial Bridge. It’s a marvel of engineering, a floating bridge that seems to defy gravity. The Homer M. Hadley Memorial Bridge carries the westbound lanes of Interstate 90, connecting Seattle to Mercer Island. This bridge isn’t just a roadway. It’s a piece of Seattle’s history, a testament to innovation and a tribute to a visionary engineer.
The Homer M. Hadley Memorial Bridge opened in June 1989. It’s officially the Third Lake Washington Bridge. It’s the fifth-longest floating bridge in the world, stretching an impressive 5,811 feet. The bridge is named after Homer More Hadley. He designed the Lacey V. Murrow Memorial Bridge, the older floating bridge that runs parallel to the Hadley. Hadley’s vision for these floating bridges was initially met with skepticism, even ridicule. Some called the idea “Hadley’s Folly.” But Hadley’s innovative design, using hollow concrete pontoons, proved to be a brilliant solution for bridging the deep waters of Lake Washington.
The Homer M. Hadley Memorial Bridge initially carried traffic in both directions. This was while the Lacey V. Murrow Memorial Bridge underwent renovations. A dramatic event in 1990 highlighted the interconnectedness of these two bridges. During a severe windstorm, sections of the Murrow Bridge sank. This also severed some of the Hadley Bridge’s anchor cables, forcing its closure for several days. Following the reopening of the Murrow Bridge, the Hadley Bridge was reconfigured. Two reversible lanes were dedicated to high-occupancy vehicles. These lanes were later closed to prepare for an even more groundbreaking development.
In 2023, the Homer M. Hadley Memorial Bridge achieved another milestone. It became the first floating bridge in the world to carry light rail. This project, a collaboration between Sound Transit and the Washington State Department of Transportation, involved strengthening the bridge. One of the remarkable feats was the installation of 3,600-foot post-tensioning strands inside the bridge. These are the longest continuous tendons in the world. The work was complex. Crews had to work within the confined spaces of the bridge’s pontoons, often while traffic continued to flow overhead. The Homer M. Hadley Memorial Bridge now carries four westbound lanes, a bicycle and pedestrian path, and two light rail tracks. It stands as a symbol of Seattle’s ingenuity, its embrace of progress, and its commitment to connecting communities across the water.