BAY BRIDGE

Description

Essentials about the Bay Bridge in brief

When you think of San Francisco, you automatically associate the city with a bridge, namely Golden Gate Bridge. But there is a second, equally spectacular bridge that spans San Francisco Bay and connects the city with Oakland on the east side of the Bay: Bay Bridge. Actually it is called “San Francisco – Oakland Bay Bridge”, but that is too long for most people. If you are traveling to San Francisco by car, you should make sure that you drive over Bay Bridge into the city, because the bridge is one of the most impressive in the entire USA and offers drivers a magnificent view of San Francisco Bay and the city when crossing it.

The architecture of the Bay Bridge

In terms of length, Bay Bridge beats Golden Gate Bridge easily. It has a total length of 8.3 kilometers. But that’s a bit of a lie, because Bay Bridge actually consists of two bridge sections with Yerba Buena Island as the “connecting piece. The western segment connects the small island to San Francisco and consists of two individual suspension bridges, each with two pylons butting up against each other at a central concrete anchor block.

The eastern segment connects Oakland with Yerba Buena Island and is composed of two parallel ramp bridges and finally a large single-span suspension bridge. The latter replaced the original bridge, a steel truss structure, in 2013. Traffic is routed on two levels in the western section; the upper deck leads toward San Francisco, the lower toward Oakland.

The history of the Bay Bridge

The first plans to cross the San Francisco Bay

Plans to build a bridge across San Francisco Bay existed as early as the 1870s. The considerations were triggered by the completion of the first transcontinental railroad in 1869, which ended in Oakland on the east side of the bay. This put San Francisco on the wrong side of the bay, so to speak, and many citizens feared that the city would lose its position as a central hub for goods and commerce. In 1872, a bridge construction committee began planning a railroad bridge. Because of the vastness of the crossing and the depth of San Francisco Bay, the engineering challenge of building a bridge seemed too great. Likewise, plans for an underwater tube were rejected.

The Bay Bridge routing

In the course of the 1920s, the demand for a bridge construction became louder and louder due to the increasing motor vehicle traffic. Finally, in 1929, then U.S. President Hoover and California Governor Young appointed a commission to study the technical feasibility and prepare recommendations. The studies were led by Charles H. Purcell, who was subsequently appointed Chief Engineer, responsible for the design and construction of the bridge. In order to make the bridge design feasible, it was decided to include Yerba Buena Island, located in the bay, thus reducing the amount of material required compared to a one-piece bay bridge. At the time, the island was a U.S. Navy base, so U.S. Congressional approval for bridge construction was necessary. Only after many years of costly lobbying did Congress give its approval in 1931.

The construction plan for the Bay Bridge

The 3.2 kilometers of the western section between the island and San Francisco were an enormous engineering challenge. The bay is 30 meters deep in places, and the subsoil required new techniques of foundation and footing. Suspension bridges with more than two pylons are very difficult to construct for stability reasons, and a single suspension bridge with only two pylons was not possible at the time because of the large span. The solution was to build a large concrete anchor block halfway between San Francisco and the island and construct two individual suspension bridges that were complete in themselves.

The eastern segment was no less complex. The distance between Yerba Buena Island and Oakland is 3.1 kilometers and was spanned with a combination of one large as well as 19 smaller truss bridges made of steel; in total, this resulted in the longest bridge of its kind. A tunnel 165 meters long connects the halves of the overall structure on Yerba Buena Island. Rock and rubble produced during tunnel construction were partly used to fill in the new neighboring Treasure Island.

The construction of Bay Bridge

Construction of the entire Bay Bridge structure began shortly after construction began on the Golden Gate Bridge in 1933. In terms of completion, Bay Bridge beat Golden Gate Bridge by six months. It was ceremonially opened on November 12, 1936. At the time of completion, it was the longest suspension bridge and also the longest truss bridge in the world. However, since it is ultimately two bridges, the western part of the suspension bridge was declared the second longest and the eastern part the third longest suspension bridge in the world.

The new construction of Bay Bridge in the 21st century

Since 2013, people no longer ride on the old truss structure on the eastern part of Bay Bridge. This had become dilapidated over the years and a decision had to be made between expensive reinforcement or a new construction. Technical as well as economic studies in 1999 showed that a new bridge would be only marginally more expensive, but would last much longer and would also be much cheaper to maintain. Public authorities therefore decided to replace the entire eastern segment except for the main bridge – a prestressed concrete structure – with a new bridge.

An architectural competition was announced for a “remarkable bridge”, a bridge with a striking and impressive unique appearance. The authorities were surprised when only one design for the tower of the new bridge was submitted at the end of the competition, and it was much more expensive than anticipated. The total projected cost of the project was more than six billion U.S. dollars, up from an original estimate of about one billion dollars. Detailed design of the East Bay Bridge replacement began in 2002, with completion scheduled for 2007. In late 2004, the governor of California announced that the original project of an impressive bridge would be overturned; instead, a simpler and less expensive structure, as originally planned, would now be built.

In 2005, the state of California reached a compromise with local authorities and the contractors to build the new suspension bridge and to charge a toll to finance it. The old bridge was closed on August 28, 2013, and the new bridge was opened on September 2 after connection to the existing access roads. Subsequently, after the commissioning, demolition work began on the old bridge.

Crossing Bay Bridge

Bay Bridge is one of the key links in California’s road network. It is used by over 250,000 vehicles every day and is correspondingly prone to congestion. In the past, accidents often paralyzed traffic for several hours. But neither the worry of traffic jams nor the toll due should keep you from crossing Bay Bridge, because the drive is a real experience (and passengers should definitely have a camera in hand for a few snapshots).