90 Engineering Ethics: An Industrial Perspective
used the East Bay Highway to travel from suburbs to the Oakland area.
Vehicles were ferried from Berkeley to Hyde Pier in San Francisco. Once in
San Francisco, vehicles used the Bay Shore Highway to travel between San
Francisco and San Mateo.
The Southern Pacific railroad also had indirect routes between the two
cities. One railroad crossing across the bay spanned Dumbarton Port in
Alameda County and Redwood City in San Mateo County; the second
crossing spanned Benicia and Martinez.
With this transportation system in place, the San Francisco–Oakland Bay
bridge began its construction in 1933. Designed only to improve highway
and mass transit services between the East Bay and San Francisco, this
bridge was congested on the day of its dedication in 1936 and has remained
congested almost without interruption (HAER, 1999).
BRIDGE DESIGN AND CONSTRUCTION
The Bay Bridge design was based on the following requirements:
• Capacity of six lanes for highway traffic and at least two operative
and one passing or emergency track for interurban trains;
• One or two bridge spans between San Francisco and Yerba Buena
island (the west channel), and one span between the island and
• Vertical and horizontal clearances of 220 feet and 1650 feet,
respectively, mandated by the War Department.
Unlike other prominent bridges built at the time, such as the Golden Gate
Bridge, the Bay Bridge was designed by committee, rather than under the
vision of one designer/architect. It was efficiently designed during a 24-month
period, from early 1931 to early 1933. In 1931 the California legislature
authorized the California Toll Bridge Authority (CTBA), which it had
created in 1929, to build the bridge and provided $650,000 for its design.
C. H. Purcell, who studied civil engineering at Stanford University, was
appointed chief engineer for the bridge; Charles Andrew, who studied civil
engineering at the University of Illinois, was named as his assistant, or bridge
engineer.When Purcell and Andrew’s requested exemption from civil service
was approved, they hired a talented team of more than 50 engineers along
with allied specialists, including surveyors, draftsmen, and a clerical staff. Two
prominent team members were Ralph Modjeski, one of the best known
bridge engineers of the early 20th century, and Daniel Moran, one of the best
known foundation engineers.
Due to the horizontal clearances requested by the War Department, a
suspension design, rather than a cantilever design, was selected for the
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