Over the past couple of years, Bay Crossings has featured many a dramatic photo of the construction of the daring and iconic new East Span of the San Francisco-Oakland Bay Bridge.
Published: November, 2011
Over the past couple of years, Bay Crossings has featured many a dramatic photo of the construction of the daring and iconic new East Span of the San Francisco-Oakland Bay Bridge. This month, we pause from examining the new East Span’s impressive construction progress and look back 75 years to the opening of the original Bay Bridge on November 12, 1936. Then as now, the bridge was considered a feat of engineering, financing and political will. Then, as the East Span is doing now, the silver bridge added sparkle to the region’s skyline, and made a profound impact on the region’s economy and commute patterns.
The opening of the original Bay Bridge in the midst of the Great Depression was marked with a gala celebration that lasted five days and nights. The activities marking the 75th anniversary will be considerably more modest by comparison — and more virtual than physical — but will be imbued with a dignity and elegance fitting for the venerable workhorse bridge (see box).
The Bridge Begins
While ferries had long carried people across the Bay’s often choppy waters, by 1936, automobiles were the future of transportation. As expected, as soon as the San Francisco-Oakland Bay Bridge was built, it immediately became the favorite way to travel between San Francisco and the East Bay.
Cynics believed that the bridge would be impossible to build due to the potential impact of turbulent waters and gusty winds. Engineers had assumed that the area’s high winds posed a greater threat than earthquakes, despite the bridge’s proximity to two major fault lines. The varying soils and water depths, the inaccessibility to bedrock, and the unique design challenges inherent in developing a bridge to span eight miles across the Bay led some to believe that building such a bridge was unthinkable.
The largest and most expensive bridge of its time, the Bay Bridge faced not just natural obstacles, but political hurdles as well. There had been discussion of building a bridge between San Francisco and Oakland since the 1870s, but construction did not move forward until the Reconstruction Finance Corporation, with support from President Herbert Hoover, agreed to purchase bonds to be repaid later with bridge tolls.
The bridge design needed to break the mold. The result was a unique bridge that combined the best elements of several different designs. The West Span, made up of two suspension bridges, allowed easy passage for the Navy and merchant ships sailing to and from San Francisco. While a suspension bridge was appropriate for spanning the deep waters near San Francisco, it was not practical for spanning the shallow mudflats near Oakland. Nor was it feasible to build a suspension bridge to span the entire distance between the two cities.
The original East Span of the Bay Bridge therefore features a truss-cantilever design, with pilings reaching hundreds of feet under the Bay to anchor the bridge. Connecting the East and West Spans at Yerba Buena Island is the world’s largest-diameter bore tunnel, which is 76 feet wide and as tall as a four-story building.At the time, the West Span’s center anchorage was taller than any building in San Francisco.
The bridge was constructed in five phases: first the East Span, followed by the tunnel through Yerba Buena Island, and then the West Span. This was followed by the Interstate-80 West approach and on- and off-ramps, and finally, the Transbay Terminal in San Francisco. The terminal housed the control center for the four railroad lines along the bridge’s lower deck. It took three years and $77 million to build the original bridge and Transbay Terminal.
In its first year, the bridge served nine million vehicles, far exceeding expectations. Today’s volume is over 102 million vehicles per year. In 1958, the bridge’s lower deck ceased carrying trains and by 1962 the bridge was reconfigured into its current configuration, with both upper and lower decks open only to vehicular traffic.
Though she may be three-quarters of a century old, the Bay Bridge is still going strong, with a seismic retrofit of the western suspension half linking San Francisco and Yerba Buena Island completed in 2004. When the new eastern half opens in 2013, the entire eight-mile bridge will be able to handle the ground motions from a 1,500-year seismic event and function as a "lifeline" route in the event of the Big One.
Stories by Brenda Kahn with historical information from BayBridgeInfo.org.
Words from the Past: Bay Bridge 1936 Gala Program
Following is an excerpt from the program for the gala multiday celebration surrounding the opening of the Bay Bridge:
"San Francisco Bay is bridged! Traffic flows over a great ribbon of steel and concrete eight and one-quarter miles long! That which has been envisioned for five decades has become a reality. Work was started on this vast project a little more than three years ago.
"San Francisco celebrates! The rejoicing is more than a tribute to the brains and brawn that went into this vast undertaking. It is more than a tribute to the engineering wonder of this decade. We celebrate a monument to the indomitable and undying spirit of the West.
"The days from November 11th to 15th are gala ones for San Francisco. Into them are crowded all the glamor and all the joyful anticipation of what the bridge will mean to the future – a future well-founded on a brilliant past."
A Year’s Worth of Celebratory Events and Exhibits
Caltrans and its partners — the Bay Area Toll Authority and the California Transportation Commission — are deeming November 2011 to November 2012 "The Year of the Bay Bridge."And they are cooking up a year’s worth of activities to mark the bridge’s 75th year, starting with a media event in early November where the 1936 bridge opening will be celebrated anew. In conjunction with the media event, the agencies plan to unveil a new outdoor interpretive exhibit that will tell the story of the new East Span. The exhibit will stand on Treasure Island, directly opposite the East Span, giving viewers a window onto the dramatic and final phases of construction of the new East Span. The display will feature QR (quick response) codes that will enable viewers to link to online information via their smart phones.
The agencies have also developed an online timeline tracking the history of the Bay Bridge from inception to current day, amplifying the story with short videos and historic photos. Also being unveiled in November is a new Facebook page where residents can post their memories of the Bay Bridge, and meet up with other bridge fans.
Outside groups are likewise working on projects to commemorate the bridge’s 75th anniversary. For starters, a pair of local artists have collaborated on "Approach, Transition, Touchdown: The San Francisco-Oakland Bay Bridge Project," which is running at San Francisco’s Electric Works gallery through November 23 (130 8th Street, SF, sfelectricworks.com). The show consists of a series of prints and drawings focusing on the historic and current construction of the Bay Bridge. Also under discussion is The Bay Lights project, in which the West Span of the Bay Bridge would become a canvas for a dynamic light installation.
Go to BayBridgeInfo.org to link to the memory Facebook page, the historical timeline and planned 75th anniversary events.
