Photo by Cliff West
Built from July 9, 1933 to November 12, 1936, the double-deck connection of Interstate 80 between Oakland and San Francisco is actually two separate bridges. The 9,260-foot West Span (pictured) is two suspension bridges connected end-to-end at a man-made anchor point. The towers of the West Span are 526 feet tall, and the bridge has 220 feet of vertical clearance above the bay. The 10,176-foot East Span (not pictured) is a combination of cantilever beams and trusses. The two spans meet at Yerba Buena Island, where they are connected by a 1,700-foot tunnel. The tunnel, at 76 feet wide and 56 feet high, is the largest-diameter bore in the world. On average, 280,000 vehicles make this crossing every day.
On October 17, 1989, the Loma Prieta earthquake caused a 50-foot section of the upper deck of the East Span to collapse onto the lower deck. The bridge was closed for a month for repairs. Today, a new East Span has been built.
This concludes the original content of my San Francisco PLACES page. To see any additional blog entries about Milwaukee, click on the San Francisco label.
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