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Evergreen Point Floating Bridge
Traffic on the Evergreen Point Floating Bridge at night, looking west.
Official name	Governor Albert D. Rosellini Bridge--Evergreen Point
Carries	4 lanes of WA 520
Crosses	Lake Washington
Locale	Seattle, WA to Medina, WA
Maintained by	Washington State Department of Transportation
Design	Pontoon bridge[1] with movable midsections
Total length	7,578 ft (2,310 m)[1]
Opening date	August 28, 1963

The Evergreen Point Floating Bridge, officially the Governor Albert D. Rosellini Bridge—Evergreen Point, is the longest floating bridge in the world at 7,578 feet (2,310 meters).^[1] It carries Washington State Route 520 across Lake Washington from Seattle to Medina and is often called the "520 bridge" by locals.^[1] Microsoft programmers often call it the "Evergreen Floating Point Bridge", a pun based on a term for numbers with decimal points often used in computers.^{[citation needed]}

It was built as a four-lane toll bridge in 1963 to provide easy access from Seattle to Eastside communities such as Bellevue, Kirkland, and Redmond. It was the second bridge to cross Lake Washington, the first being the Lake Washington Floating Bridge, built in 1940 as part of U.S. Route 10, later part of Interstate 90, which at its construction was the largest floating structure ever built. Tolls were lifted from the Evergreen Point Bridge in 1979, and the wide area where tolls were collected is now used for bus stops. In 1988 the bridge was named for Rosellini, who had pushed for its construction.

The bridge carries 115,000 vehicles per day but was only designed to carry 65,000.^[2] Due to this bottleneck, commuters often follow the motto "anything but the 520 bridge" during peak traffic, with I-90 or even a northbound loop around the lake via Bothell and Kenmore preferred as alternate routes. Because Microsoft, one of the area's largest employers, is on the Eastside just off 520, traffic on the bridge tends to be heaviest west-to-east (away from Seattle) in the morning and east-to-west (toward Seattle) in the evening, backward from what one might expect. (The I-90 floating bridge has more typical traffic patterns, with commuters going into Seattle in the morning and returning east in the evening.) Commuters often use this knowledge to take the bridge with the least traffic for their desired trip at various times of day. Electronic signs on I-405 display estimated times to Seattle for both 520 and I-90 routes.

Scenery visible westbound on clear days include the Olympic Mountains and Husky Stadium on the University of Washington campus, as well as two metal sculptures. Eastbound are expensive waterfront homes in Medina, including the large home of Bill Gates on the southern side, which is extensively lit in the holiday season. On clear days, Mount Baker is visible to the north, the Cascade Mountains are the backdrop, and Mount Rainier is to the southeast. Mercer Island is to the south. On July 4, fireworks are visible from many communities and homes along the lake.

The bridge incorporates an infrequently-used drawspan to allow large vessels to pass; Smaller vessels pass under the "high rises", elevated portions of the bridge on each end. The drawspan is also opened during major storms to relieve water pressure.

In 2000, a gravel barge (whose captain was dozing at the wheel) struck the bridge, closing it for eleven days and causing $500,000 worth of damage. In 1989, an electrical fault caused the drawspan to open during rush hour, causing one death and five injuries.

Today the bridge is near the end of its useful life, according to the state Department of Transportation. The bridge must be closed in high winds, and even after a seismic retrofit in 1999, it is at risk of collapse in an earthquake. Due to the weight of various reinforcements over the years, the bridge currently rides about a foot lower in the water than it did originally. The DOT is working on replacing the aging bridge with a new span of six lanes.^[3]

The bridge is anchored by a large number of high-strength cables. According to an interview conducted by local newspapers, a severe storm during the bridge's lifespan came within strands of breaking some of these cables, which would have resulted in the catastrophic collapse of the bridge. Since then, additional cables have been added, and much of the bridge has been replaced with lighter materials, but the danger remains. The bridge was originally designed to stand up to a 100-year storm, but the assumptions used actually reflected what is now considered to be a 20-year storm for the Seattle area.

• Evergreen Point Bridge in the Structurae database
• Bridge camera (includes some weather data)
• Department of Transportation photo gallery

• Evergreen Point Floating Bridge is at coordinates 47°38′26″N 122°15′37″W / 47.64051, -122.26019Coordinates: 47°38′26″N 122°15′37″W / 47.64051, -122.26019