Golden Gate Bridge

The Golden Gate is the mile-wide strait of water that separates San Francisco from Marin County at the mouth of the San Francisco Bay. There are 10 streams running into the bay and out into the ocean through this small channel, which turns into a swirling mass of currents as the ocean tides force water back through it. The English name was already in use before the 1848 gold rush in San Francisco had started and, it’s been suggested, the name in fact refers to the Golden Horn in Istanbul, the harbor at the mouth of the Bosporus, which separates Sea of Marmara from the Black Sea and is also famous for its dangerous currents. A ferryboat ran from San Francisco to Sausalito in Marin County until 1937, when the Golden Gate Bridge was opened. Ever since then, its dazzling design and unique color, known as international orange and originally used to make the bridge more noticeable in the fog, along with its appearance in several movies, have made it one of the most recognizable bridges on the planet.

The thinking behind constructing a bridge across the Golden Gate had been around since at least 1917, but was given great inspiration by the structural engineer Joseph Strauss, who became involved in 1921. He had designed many bridges before, but nothing on anywhere near the size of the Golden Gate Bridge. In the beginning his designs were declined, mainly on aesthetic grounds, but, after a decade of redesigning and campaigning, and also with the help of the engineer Charles Ellis, the architect Irving Morrow, who was responsible for the Art Deco look of the bridge and select the color, and the bridge designer Leon Moisseif, construction work started.

The style and design of the bridge needed the primary towers to be sited in the strait, which caused a lot of delays and resulted in the project going substantially overbudget. This very first attempt involved using scuba divers, but this turned out too dangerous in the current. A jetty was constructed out to the site of the foundations from the banks, but a freighter ran into it in the fog and then it was blown down in a storm. When the foundations were eventually completed, the two suspension towers were built on them. Joseph Strauss was much more safety conscious than was usual at the time and insisted on measures for example harnesses and hard hats for the laborers. An enormous net was also slung under the bridge to catch anybody who fell off and it is credited with saving nineteen lives.

Despite this, sixteen people were killed when part of one of the towers collapsed. The primary suspension cables, each comprising 27,000 galvanized wires spun together into cables, were strung between the towers and were sealed and clad in steel to prevent them rusting. The suspension cables were then installed, going down from the main cables to the suspended deck, on which the roadway was laid. When it was opened in 1937 it was the longest suspension bridge on the planet, a title it held until the Verrazano-Narrows Bridge in New York was built in 1964.

In 1989 the Loma Prieta earthquake, which measured 6.9 and killed 62 people in the San Francisco area, struck. The Golden Gate Bridge survived relatively intact but part of the Bay Bridge collapsed and led to what has been called seismic retrofitting at the Golden Gate, which became particularly pertinent when it was calculated that an earthquake of the magnitude of the 1906 quake, which was 7.9 and killed 3,000 people, would have destroyed the bridge. It is now being equipped to survive an 8.3 earthquake and, as the engineer in charge of the project has explained, anything higher than that and there will be no need to worry about the bridge because San Francisco will have been flattened anyway. The retrofitting involves, in effect, completely rebuilding the bridge piece by piece while, at the same time, increasing its ability to dissipate seismic forces and separating each section of the bridge with isolation bearings. As long as the next earthquake doesn’t hit before the project is finished, the bridge should be standing for many years to come.

A further problem has been to try to reduce the number of people committing suicide by jumping off the bridge, which now runs at around one suicide every two weeks. There have been proposals to fit suicide barriers, which have come to nothing so far, and pedestrians are no longer allowed onto the bridge at night, but, unfortunately, people still choose this beautiful bridge, 220ft (67m) above the currents of the Golden Gate, as the place to end it all when they can go on no further.