The iconic Golden Gate Bridge began construction in San Francisco on January 5, 1933. The orange-coloured bridge, whose construction took more than four years, is a steel suspension bridge 2.74 km long and 90 ft wide. It stretches across the Golden Gate, a narrow passage that extends for one mile and connects San Francisco Bay and the Pacific Ocean.
An Engineering Wonder
The massive engineering marvel connects the city of San Francisco in California to Marin County. The idea of spanning the Golden Gate Strait through a bridge was there for over a century before the Golden Gate Bridge was opened to traffic on 28th May 1937. It was the longest suspension bridge in the world when it was constructed, and its construction cost was 35 million USD in 1937. If adjusted for inflation, constructing this bridge would cost 1.5 billion USD in 2016.
Joseph Strauss was the chief engineer for the project to build this massive bridge. Leon Moisseiff, Irving Morrow, and Charles Ellis contributed significantly to this architectural wonder’s impeccable aesthetic and majestic design.
According to the Golden Gate Bridge Highway & Transportation District website, the Golden Gate Bridge features two primary cables spanning over the summits of the two 746-foot-tall towers, securely anchored at each end in massive anchorages. Each main cable is constructed of galvanised carbon steel wire, which was installed by spinning the wire using a shuttle mechanism that moved back and forth to position the wire and form the cables. The process of spinning the wires for the main cables was completed in 6 months and 9 days. Each cable comprises 27,572 wires. If the wires were kept in one continuous length, they could wrap the earth over three times!
Reversible lanes were inaugurated on the bridge on 29th October 1963. Their use greatly facilitates traffic flow during the heavy morning and evening commuting hours and during weekend tourist periods.
The bridge has six lanes, with northbound and southbound lanes separated by a moveable median barrier. The barricade is a structure made of concrete and steel, measuring one foot in width and 32 inches in height. It serves as a secure separation between lanes of traffic and replaced the bright yellow lane markers that were earlier used to separate opposing traffic lanes.
Huge Economic Impact
Today, this bridge carries about 40 million vehicles on average a year. It serves not only as a vital transportation link but also as a major global travel destination for millions of visitors from around the planet. The American Society of Civil Engineers has acknowledged the bridge as one of the marvels of contemporary engineering. It is widely considered to be the most photographed bridge globally.
The economic impact of the bridge is nothing short of immense or rather immeasurable. On average, the structure earns more than $145 million in annual revenue, and tolls from automobiles account for about 70 percent of its annual income. However, that is not even a pittance compared to the tangible and intangible benefits the bridge has accrued to the US economy over the last 86 years through its vital transportation link. The bridge also contributes hugely to the US tourism revenues.
