Facts About the Construction of the Golden Gate Bridge
Kanika Khara
The Golden Gate Bridge is an 8,981 feet suspension bridge connecting the San Francisco Peninsula to Marin County. To know more about this magnificent bridge, read on.
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The Golden Gate strait is at the headlands of the San Francisco Peninsula and the Marin Peninsula. Before the bridge was built, ferry services were used by people to travel across the San Francisco Bay.
Many ideas regarding the construction of a bridge across the bay were considered, however, nothing materialized until a proposed design for the bridge published by the San Francisco Call caught the interest of the city's chief engineer. The estimated cost of constructing the bridge was $100 million, a staggering amount in those days.
After receiving permissions from all the concerned authorities, the city planners went ahead and hired Joseph B. Strauss as the chief engineer, along with other experts to work on the design and construction of the bridge. Charles Alton Ellis was chosen as the main engineer of the project.
Construction
Construction of the Golden Gate Bridge began on 5th January, 1933. Building the suspension bridge was a treacherous feat, considering the high winds and turbulent currents.
Given its enormity, a large number of fatalities were expected during the bridge's construction. However, Strauss' use of movable safety netting beneath the construction site saved many lives.
Towers
The making of this bridge led to several innovations in bridge-building technology. Its two towers design was based on Moisseiff's Philadelphia-Camden Bridge. This bridge featured large steel-cell cross-members, each set within a rectangle as its anchorage.
Large excavations were carved out on the Marin and the San Francisco sides, to lay the base for the towers. The San Francisco tower was formed using 30-ft. thick concrete fenders, that enclosed a space as big as a football field. Approximately 9.7 million gallons of water was pumped out from the fender and filled with concrete.
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The San Francisco tower was built 1,100 feet from shore. On the Marin side, the tower was built on the shoreline land. The steel base of the tower were set into concrete foundations.
Cranes were used to lift parts of the steel tower and placed atop one another and fastened by rivets. Each tower contained approximately 600,000 rivets, and weighed 44,000 tons.
Cables
The two main suspension cables were an engineering marvel. Each cable measured 7,659 feet in length and used hundreds of wires bound together to make a cable just over three feet in diameter.
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The steel wires used in the construction of the bridge was made in New Jersey, Maryland, and Pennsylvania, and the supply was shipped through the Panama Canal. More than 80,000 miles of steel wire, weighing nearly 83,000 tons, was used to build the suspension cables.
It took over six months to just spin the cables before inter-connecting them to the main suspensions. The inter-woven and inter-connected cables were held together with approximately 1,200,000 rivets.
Lighting
Lighting a bridge of this magnitude required immense planning, and was entrusted to the consulting residential architect Irving Morro.
He designed the overall lighting and art deco elements as per the need of the bridge, keeping in mind its stretch and availability of different types of lighting in those times. Lights were also installed on towers, piers, cables, railings, walkways, midspan, and on the airway beacon atop each tower.
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The construction of the bridge was completed by April 1937, and more importantly, was done nearly $1.3 million under budget. It was officially declared open on 27th May, 1937. The first day, more than 200,000 people crossed by foot and roller skates to enjoy the view.
The next day President Roosevelt pressed a telegraph key, announcing its opening to vehicular traffic. The Golden Gate Bridge is a major tourist attraction and was ranked fifth on the 'List of America's Favorite Architecture' by the American Institute of Architects in 2007.