The Golden Gate is one of the modern engineering wonders. Located in the liberal city of San Francisco, this marvelous bridge will amaze engineers and general public equally.
San
Francisco Bay is Alcatraz, the trams, Silicon Valley, sea lions at the pier 39,
live music, homeless, Berkeley University, the Golden Gate Park, freedom…but
above all, when we think about San Francisco there is one place that comes to
our minds: the Golden Gate Bridge.
The bridge from the viewpoint located on
San Francisco’s side. (Own picture)
Before
the construction of the bridge, the only route between San Francisco and Marin
County was by ferry. The population growth in the Bay area made necessary a
permanent link, but many said it was impossible to build due to the weather
conditions (strong winds and dense fogs) and geography (6,700 ft-2,042 m
strait, and 372 ft-113 m water depth at the center of the channel).
Design:
The designated Chief Engineer for the Golden Gate Bridge was Joseph Strauss, a
bridge designer from Chicago, who had developed his career with movable bridges,
until he moved to California. Despite his experience in trunnion bascule bridges,
he did not have relevant experience in suspension bridges. His first design was
a hybrid cantilever and suspension structure, so grotesque that everybody
rejected it and agreed to find a more esthetic solution. The Consulting
Engineer Leon S. Moisseiff proposed a suspension bridge without cantilever, with
a span never tried before for that type. Nowadays, we know that another Engineer
named Charles Alton Ellis performed the checking calculations and the
corrections that ensured the durability of the bridge. Strauss dismissed Ellis
fearing that his name could be eclipsed. Today a small plaque recognizes Ellis
as a big contributor to the bridge conception, but he died without all the honors
he deserved.
Strauss’ bizarre first
design (http://www.historicbridges.org/)
Art
Deco: The designs of Strauss had an inelegant mechanical look, and after the
rejection of his first proposition he realized that the bridge would be a
fusion of functionality, economy, form and beauty. Finally, the consulting architect
Irving Foster Morrow was entrusted with the project. We owe him the sleek,
simple, modern towers, and the elegant curve of cables. He simplified the
bridge lines, so our eyes go to the clean towers and cables, instead of the old-fashioned
truss structure.
Color:
At the first the Navy wanted the bridge to be painted with black and yellow
stripes to ensure visibility in the foggy bay, but fortunately Morrow convinced
them and chose the characteristic orange vermillion called international
orange.
Golden Gate Bridge
Structures (http://goldengatebridge.org)
The GGB view from
Baker Beach. (Own picture)
View of the Golden
Gate from the central yard of Alcatraz prison, as a constant reminder of the
wonder of free life. (Own picture)
There
is a viewpoint on the San Francisco side which you can reach by public bus or
even go driving and park your car there. Click on the link for further info.
Facts:
Location: San Francisco, California.
Cost: $35 million (around $1.2 billion today).
Construction time: 4 years, 4 months and 23 days.
Opening date: May 27, 1937.
The Bridge:
Total length: 1.7 miles (8,981 ft or 2,737 m).
Length of suspended span (distance between towers): 4,200 ft (1,280
m).
Width of Bridge is 90 ft (27 m).
Clearance above mean higher high water: 220 ft (67 m).
Steel rivets: 1.2 million.
Main Tower:
The Golden Gate Bridge has two main towers that support the two main
cables.
Height of a tower above water: 746 ft (227 m).
Main Cable Stats:
Diameter of one main cable including the exterior wrapping: 36
3/8 in (0.92 m).
Length of one main cable: 7,650 ft (2,332 m).
Weight of main cables, suspender cables, and accessories: 24,500
tons.
More info:
Info
and Tickets http://goldengatebridge.org/research/
75th
Anniversary http://goldengatebridge75.org/
Find
more pictures and info here:
Other
sources:
http://goldengatebridge.org/research/documents/art_deco_GGB.pdf
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