The By Bridge is the one you see snaking across the bay from San Francisco, to Yerba Buena Island, and then on to Oakland. It is an icon of San Francisco, and present in most views of the bay. After three and a half years of construction, the 8 1/2 mile long bridge was opened on November 12, 1935. It cost the lives of 27 construction workers during it's depression era creation.
The exact location of the bridge was dictated by a bedrock ridge that lies 200 feet below the surface of the bay on the line where the Bay Bridge currently sets. On either side of this ridge, the water is quite a bit deeper.
The Bay Bridge noteworthy facts include the following?
1. The lower deck was originally built for electric train traffic only. The upper deck was used for two-way vehicle traffic. This changed in 1958 when the lower deck became refitted for eastbound traffic, and the upper deck was reserved for westbound traffic.
2. The total coast was $77 million dollars.
3. President Hoover, a graduate of the Stanford School of Engineering, took a personal interest in this project. That's right, President Hoover was an engineer.
4. Halfway between San Francisco and Yerba Buena Island, it became necessary to build another island for support. The depth was to great for divers to work from the bottom up, so they tried something different and built this cement tower from the top down, eventually securing it with large steel pipes once it reached the bottom of the bay. The tower is the height of a 48 story building.
Residents of San Francisco are well aware of the troubles the bridge between Yerba Buena Island and San Francisco has had in the past 25 years. During the Loma Prieta Earthquake, part of the upper deck crashed on to the lower deck during rush hour, and more recently the bridge was closed to repair a fissure that was discovered as they began construction on a new bridge that will span the length of Yerba Buena Island to Oakland. They tried to repair the fissure in a brief amount of time, but when the bridge was reopened, the repair came crashing down on a vehicle during rush hour and caused the closer of the bridge for a week. As you work your way across this old span of bridge, you can view the new bridge beside it which will replace this ailing section around 2013.