Building History

This floating bridge, the longest in the world when built, accommodated two lanes of traffic going east and west. Engineer Henry More Hadley (1885-1967), who worked with the Seattle School District and later the Portland Cement Company, devised the bridge's radical floating concrete pontoon design, first proposing the idea at a American Society of Civil Engineers (ASCE) conference in 1921. His design was necessitated by Lake Washington's unusual depth, between 150 and 200 feet deep under the bridge's path. Over millions of years, seven periods of glaciation have influenced the topography of Puget Sound, the last being the Vashon Stade, at its largest extent 13,000 years ago. Glacial scouring and the effects of subglacial meltwater flows carved away deep troughs throughout Puget Sound region, depressions that were ultimately filled in by seawater and later freshwater; one of these topographic gouges became Lake Washington. Due to lake's great depth and soft bottom conditions, sinking pilings for a conventional bridge would become impractical and costly. By 1937, the Roosevelt Administration and Congress released federal funds for large public works. With this incentive of federal assistance, Hadley's unorthodox idea began to appeal to state highway administrators, including Lacey V. Murrow (1904-1966), the second Director of the Washington State Highway Department (1933-1940) and the Chief Engineer of the Washington Toll Bridge Authority (1937-1940). With his backing in 1937-1938, Hadley's floating span concept was accepted and completed in 1939-1940. (Soon after the bridge's completion in 09/1940, Lacey Murrow resigned his State of WA positions to become a decorated pilot for the US Army Air Corps and never again resided in WA.) A mix of federal money and tolls paid the 3,000 people who worked on the bridge. Tolls collected from 1940-1946 defrayed the bridge's $5.5 million cost; approximately a million cars traveling over the bridge per year were needed to pay off the debt. The State of WA renamed the bridge in Lacey Murrow's honor in 1967, two years after his death from lung cancer. (Tragically, lung cancer also ended the life of Lacey's brother, famed CBS News commentator, Edward R. Murrow [1908-1965].) The Murrow Bridge was rebuilt in the years after its sinking in 1990 to carry eastbound traffic on U.S. Interstate 90; westbound traffic during peak hours was carried on the parallel Homer M. Hadley Bridge (completed in 1989) located to the north of the Murrow span.

Building Notes

The Lake Washington Floating Bridge, spanned one-and-a-half miles and floated on water often 200 feet deep; construction began 12/29/1939 and finished 07/02/1940; at the time of its completion, it was the longest floating bridge in the world and weighed 100,000 tons; Governor Clarence D. Martin (1886-1955) presided at its opening ceremony to which 11 Western U.S. governors, the Premier of British Columbia and the Governor of the Territory of Alaska were invited. According to the Seattle Times of 06/16/1940: "The ceremonies are part of a 'one-two-three' dedication in the first week of July, celebrating completion of $22,500,000 in public projects in the Puget Sound area. July 1 the Narrows Bridge will be opened at Tacoma, linking the west and east side of Puget Sound, July 2 and 3 will honor the Lake Washington project, and July 3 also will mark the official opening of the $7,000,000 McChord Field, huge Army base north of Fort Lewis." (See "Pioneer Will 'Launch' Pontoon Bridge July 2 Details of Big Civic Celebration Announced," Seattle Times 06/16/1940, p. 9.) Paul Dorpat noted of the opening ceremonies: "About 2,000 people watched from the tunnel plaza area here on the bridge's Seattle side, and hundreds more gathered around toll booths at the bridge's Mercer Island end to attend the christening, which was broadcast by radio nationwide. Kate Stevens Bates, daughter of Washington Territory's first governor, Isaac Stevens, let swing and crash against the concrete bridge a yellow urn in which were mixed the waters of 58 of the state's waterways: lakes, bays and rivers." (See "Paul Dorpat, "A Bridge to Progress," Seattle Times Pacific Northwest, 03/27/2011, p. 18.) On 06/11/1979, the Murrow Bridge was named a City of Seattle Landmark.

Demolished; 850 meters (approximately 2789 feet) of this floating span sank to the bottom of Lake Washington during a storm in 11/25/1990. It sank after State of Washington Department of Engineers had started work to widen the bridge. In order to do this, sidewalks were blasted away with water sprayed at high pressure; this water, because it was considered polluted, was not allowed to flow into Lake Washington, and had to be stored somewhere. Engineers decided to store it in the pontoons supporting the bridge. Workers for the Traylor Brothers Construction Company broke six-foot holes in some pontoons into which they intended to pump waste water, but fierce storms on 11/22-24/1990 filled them with rainwater and lake water as well. Overloaded, one pontoon sank causing all of the other pontoons chained to it to drag the bridge to the bottom.