Archives West Finding Aid

When the Lacey V. Murrow Bridge opened in July 1940, it was the first reinforced concrete floating bridge ever built and the largest floating structure in the world. The Lake Washington floating bridge greatly reduced travel time and distance between Seattle and the Eastside. In 1939, ferries transported nearly a million foot passengers across Lake Washington, or motorists used a dangerous one-lane road around the lake traveling between Seattle and the rural communities of Kirkland, Bellevue and Mercer Island.

Preliminary work on the project began in 1937, funded by $4 million from the Public Works Administration and a local bond issue of $5.5 million to be repaid with tolls. The bridge was named in honor of Lacey V. Murrow (1904-1966), Washington’s Director of Highways. In 1937, Murrow approved the controversial plan for a concrete pontoon floating bridge. The Murrow Bridge was originally the brainchild of engineer Homer Hadley, who in 1921 proposed a “floating concrete highway, permanent and indestructible, across Lake Washington.”

The entire construction project was approximately 7 miles in length, beginning at Rainier Avenue in Seattle and terminating east of Lake Washington near the small community of Factoria. It was a complex, multi-contract process that included acquiring right-of-way, demolition, grading, paving, drilling a twin-bore tunnel, manufacturing and anchoring the pontoon bridge structures, and constructing the Mercer Island Roadway, East Channel Bridge, Mercer Slough Viaduct and Toll Plaza. The twin Mt. Baker Ridge Tunnels were the world’s largest diameter soft-earth tunnels ever drilled in 1940. The 25 concrete pontoon bridge sections were constructed on Harbor Island and then towed across Elliott Bay through the Ballard Locks into Lake Washington. The project was completed within budget and on schedule, without worker fatality.

Beginning in 1989, the bridge underwent repairs and renovation, including the construction of a parallel span to accommodate the increase in traffic between Seattle and the burgeoning Eastside. As part of this construction, in November 1990 workers drilled holes into the hollow concrete pontoons to temporarily store run off water from the hydrodemolition. While the pontoons doors were still open a storm hit, bringing strong winds and heavy rain. The pontoons filled with lake and rain water and begun to submerge, causing the original bridge deck to sag, break, and gradually sink to the bottom of Lake Washington. The cost of the disaster was $69 million; a new Lacey V. Murrow bridge opened the following summer.

The Lacey V. Murrow Bridge, Mt. Baker Ridge Tunnels, and the east portal relief sculptures are designated Seattle Historic and National Engineering Landmarks.