Golden Gate Bridge

The Golden Gate Bridge is a suspension bridge across the Golden Gate. This is a one-mile-wide strait linking San Francisco Bay and the Pacific Ocean in California, United States. The bridge connects San Francisco—the northern tip of the San Francisco Peninsula—to Marin County. It carries U.S. Route 101 and California State Route 1, and is also for pedestrians and bicycles, as part of U.S. Bicycle Route 95. It is one of the Wonders of the Modern World and a famous symbol of San Francisco and California.

People wanted a bridge between San Francisco and Marin County in the late 19th century. It became possible in the early 20th century. Joseph Strauss was the chief engineer, with help from Leon Moisseiff, Irving Morrow and Charles Ellis. The bridge opened to the public on May 27, 1937 and has had many improvements since.

The Golden Gate Bridge is called "possibly the most beautiful, certainly the most photographed, bridge in the world." When it opened in 1937, it was the longest and tallest suspension bridge in the world, until the Verrazzano–Narrows Bridge and Akashi Kaikyo Bridge. Its main span is 4,200 feet (1,280 m) and its total height is 746 feet (227 m).

History

Ferry service

Before the bridge was built, the only way to travel between San Francisco and Marin County was by boat across San Francisco Bay. A ferry service began in 1820, with regular trips starting in the 1840s.

In 1867, the Sausalito Land and Ferry Company began operating. By 1920, the service was taken over by the Golden Gate Ferry Company, which later merged with the Southern Pacific Railroad in 1929. The ferry trip between Hyde Street Pier in San Francisco and Sausalito Ferry Terminal in Marin County took about 20 minutes and cost $1.00 per vehicle before 1937. The trip from the San Francisco Ferry Building took 27 minutes.

Many people wanted to build a bridge to connect San Francisco to Marin County. San Francisco was the largest American city still relying mainly on ferry boats.

Conception

The idea of a bridge across the Golden Gate was not new, but it became serious in 1916. James Wilkins wrote about it in the San Francisco Bulletin. Joseph Strauss, an engineer, offered to build it.

Strauss spent over ten years gathering support. The bridge faced many challenges, including concerns from the Department of War about ship traffic and opposition from the powerful Southern Pacific Railroad. In 1924, Colonel Herbert Deakyne approved using federal land for the bridge. The bridge's name, the Golden Gate Bridge, was first used in 1917 and became official in 1923.

Design

Strauss was the chief engineer for the bridge, but he needed help with the design. Leon Moisseiff, who designed the Manhattan Bridge, came up with the final suspension design. Irving Morrow designed the bridge's towers and its famous International Orange color. Charles Alton Ellis did much of the technical work.

Finance

The Golden Gate Bridge and Highway District was created in 1928 to build the bridge. After the Wall Street Crash of 1929, they needed help raising money. In 1930, they got approval for a $30 million bond measure, but they couldn’t sell the bonds until 1932 when Amadeo Giannini from Bank of America agreed to buy them.

Construction

Construction started on January 5, 1933. It cost more than $35 million and was finished early and under budget. Strauss introduced safety netting that saved many workers.

The Round House Café diner was built at the southeastern end of the bridge and became a popular spot for tours and gifts.

Torsional bracing retrofit

In 1951, strong winds showed that the bridge could sway and roll. Between 1953 and 1954, the bridge was strengthened with new bracing.

Bridge deck replacement (1982–1986)

The original concrete deck got damaged by salt from fog, so from 1982 to 1986, it was replaced with lighter and stronger steel panels over many nights without closing the bridge completely.

Opening festivities, and 50th and 75th anniversaries

The bridge opened in 1937 with a week-long celebration. On the day before cars were allowed, 200,000 people walked or roller-skated across. On opening day, officials crossed the bridge in a motorcade. Later, President Franklin D. Roosevelt pressed a button in Washington, D.C., to officially open the bridge to traffic.

For the 50th anniversary in 1987, the bridge was closed to cars so people could walk across. For the 75th anniversary in 2012, special solar beacons were added to the towers.

Structural specifications

Until 1964, the Golden Gate Bridge had the longest main span in the world. Since then, twenty bridges have been built that are longer, and it now holds the second-longest main span in the Americas, after the Verrazzano–Narrows Bridge in New York City. The total length of the bridge from end to end is 8,981 feet.

The bridge's towers stand 746 feet above the water. The roadway hangs from 250 pairs of ropes attached to two main cables. Each cable is made of many strands of wire, with a total length of 80,000 miles of galvanized steel wire. Each tower contains about 600,000 rivets.

Aesthetics

People liked the look of the Golden Gate Bridge very much. The first design was changed to add nice details like lighting on the cables and towers. In 1999, it was picked as one of America’s favorite buildings.

The bridge has a special orange color called international orange. This color was chosen to look nice with the nearby nature and to help people see the bridge better in foggy weather.

The bridge used to be painted with a special red paint, but this was changed in the 1960s to protect it better from rust. Now, the bridge is kept looking fresh by a team of painters who work on it all the time.

Traffic

The Golden Gate Bridge connects San Francisco and Marin County, California. It has space for cars, people walking, and bicycles.

The bridge changes its traffic lanes several times a day. On weekday mornings, most traffic goes south toward the city. In the afternoons, traffic goes north. On weekends, traffic is split evenly.

The bridge is busy, with many cars passing over it each day. It is also popular with people walking and riding bicycles. There are special times for pedestrians and bicyclists on the bridge walkways.

Navigational aid

Beacons

The Golden Gate Bridge has special lights to help airplanes and ships see it clearly. Bright red lights on the towers warn airplanes. At night, red lights on the cables show the bridge. For ships, the bridge has white and green lights in the middle and red lights on the south tower.

Foghorns

Fog can cover the bridge, making it hard for ships to see. The bridge has five foghorns that make loud sounds to help ships. These foghorns have been used since 1937 and still work today. Two foghorns are at the base of the south tower, and three are in the middle of the bridge. The sounds help ships know where the bridge is and stay safe.

Issues

Protests and stunts

Since the late 1970s, the Golden Gate Bridge has seen many protest rallies. Sometimes, people did bold actions to get attention for their messages by climbing the bridge. For example, on November 24, 1996, actor Woody Harrelson joined local environmentalists who hung a big banner to speak out against a CEO’s actions regarding logging. This caused traffic delays all day. To prevent more disruptions, a law was passed in 1997 to make it harder to break onto the bridge. Still, protests have kept happening, sometimes closing the bridge completely. For example, in June 2020, people took over the bridge to speak out against police brutality after the George Floyd's murder. In November 2021, a crash happened during a protest against government-mandated COVID-19 vaccinations. In February and April 2024, people also stopped traffic to speak out about the Gaza war.

Wind

The Golden Gate Bridge was built to handle winds up to 68 mph (109 km/h). Before 2008, the bridge was closed only three times because of strong winds. In June 2020, people in San Francisco and Marin Counties started hearing a strange humming noise from the bridge. This noise happens when wind blows through new, flexible parts added to the bridge to help it handle even stronger winds—up to 100 mph (161 km/h). The bridge makes two different sounds depending on the wind speed and angle. In December 2021, plans were approved to add special clips to reduce the noise. These clips are expected to lower the noise by 75%, though the bridge will still make some sound about 70 hours a year.

Seismic vulnerability and improvements

Because the Golden Gate Bridge is close to the San Andreas Fault, there is a risk of earthquakes. Engineers worked on ways to make the bridge stronger. A big project worth $392 million was started to help the bridge survive earthquakes with only small damage that can be fixed. This work was very careful so that people could still use the bridge every day. The old road leading to the bridge, Doyle Drive, was replaced with a new one called the Presidio Parkway, which opened in July 2015. The old road was taken down in April 2012 because it could be damaged in an earthquake and had problems with its design.