Lacey V. Murrow Floating Bridge: I-90 Across Lake Washington

On the morning of July 2, 1940, Seattle dedicated the Lake Washington Floating Bridge. Some people called it the Mercer Island Bridge. It carried US 10 across the lake, from the Mount Baker neighborhood of Seattle, over Mercer Island, to a point south of Bellevue. US 10 was later decommissioned and renamed Interstate 90. At the time it was the largest floating structure ever built, and the first bridge to cross Lake Washington. [1]

The idea was older than the bridge. Engineer Homer Hadley first conceived it in 1921. Instead of piers sunk into the lakebed, the roadway floats on hollow concrete pontoons. That was an innovative technology when it was built. The whole thing cost $8,854,000. [1]

The opening day was a party. Two thousand people gathered on the east side. A ribbon was cut, and an urn holding water from 58 Washington streams and lakes was smashed against the side of the bridge. The Seattle Breakfast Club ate under the west approach while an Army band played. Later came swimming races, fancy diving, surfboarding and water skiing. Governor Clarence D. Martin paid the first toll. Most tolls were for cars, but the schedule also listed 35 cents for a wagon pulled by one or two horses and 50 cents for three or more. The bridge saved commuters up to an hour on the trip to Seattle. [1]

The design had one famous flaw. A sliding draw span in the middle created a bulge, and drivers had to make a sharp turn at highway speed. The bridge became notorious for accidents, some of them fatal. In 1981 the state replaced the bulge with straight pontoons. In 1967 the bridge had been renamed the Lacey V. Murrow Memorial Bridge, and in 1989 a parallel twin, the Homer Hadley Bridge, was completed beside it. [1]

Then, on November 25, 1990, the bridge sank. It had been under repair, and workers had left hatches to the hollow pontoons open. A storm filled them with water. The bridge was later rebuilt. Today it is part of I-90 between Seattle and Mercer Island. Its east end meets the Mount Baker Tunnel, which links it to the city. [1][2]