The Golden Gate Bridge is a suspension bridge spanning the Golden Gate, the opening of the San Francisco Bay into the Pacific Ocean. As part of both U.S. Route 101 and California State Route 1, the structure links the city of San Francisco on the northern tip of the San Francisco Peninsula to Marin County. The Golden Gate Bridge was the longest suspension bridge span in the world when it was completed in 1937, and has become one of the most internationally recognized symbols of San Francisco, California, and of the United States. Despite its span length being surpassed by eight other bridges since its completion, it still has the second longest suspension bridge main span in the United States, after the Verrazano-Narrows Bridge in New York City. It has been declared one of the modern Wonders of the World by the American Society of Civil Engineers. The Frommers travel guide considers the Golden Gate Bridge "possibly the most beautiful, certainly the most photographed, bridge in the world".
Before the bridge was built, the only practical short route between San Francisco and what is now Marin County was by boat across a section of San Francisco Bay. Ferry service began as early as 1820, with regularly scheduled service beginning in the 1840s for purposes of transporting water to San Francisco. The Sausalito Land and Ferry Company service, launched in 1867, eventually became the Golden Gate Ferry Company, a Southern Pacific Railroad subsidiary, the largest ferry operation in the world by the late 1920s. Once for railroad passengers and customers only, Southern Pacific's automobile ferries became very profitable and important to the regional economy. The ferry crossing between the Hyde Street Pier in San Francisco and Sausalito in Marin County took approximately 20 minutes and cost US$1.00 per vehicle, a price later reduced to compete with the new bridge. The trip from the San Francisco Ferry Building took 27 minutes.
Many wanted to build a bridge to connect San Francisco to Marin County. San Francisco was the largest American city still served primarily by ferry boats. Because it did not have a permanent link with communities around the bay, the city's growth rate was below the national average. Many experts said that a bridge couldn’t be built across the 6,700 ft (2,042 m) strait. It had strong, swirling tides and currents, with water 500 ft (150 m) in depth at the center of the channel, and frequent strong winds. Experts said that ferocious winds and blinding fogs would prevent construction and operation.
Construction began on January 5, 1933. The project cost more than $35 million. The Golden Gate Bridge construction project was carried out by the McClintic-Marshall Construction Co., founded by Howard H. McClintic and Charles D. Marshall, both of Lehigh University.
Strauss remained head of the project, overseeing day-to-day construction and making some groundbreaking contributions. A graduate of the University of Cincinnati, he placed a brick from his alma mater's demolished McMicken Hall in the south anchorage before the concrete was poured. He innovated the use of movable safety netting beneath the construction site, which saved the lives of many otherwise-unprotected steelworkers. Of eleven men killed from falls during construction, ten were killed (when the bridge was near completion) when the net failed under the stress of a scaffold that had fallen. Nineteen others who were saved by the net over the course of construction became proud members of the (informal) Halfway to Hell Club.
The project was finished by April 1937, $1.3 million under budget.
As the only road to exit San Francisco to the north, the bridge is part of both U.S. Route 101 and California Route 1. The median markers between the lanes are moved to conform to traffic patterns. On weekday mornings, traffic flows mostly southbound into the city, so four of the six lanes run southbound. Conversely, on weekday afternoons, four lanes run northbound. Although there has been discussion concerning the installation of a movable barrier since the 1980s, only in March 2005 did the Bridge Board of Directors commit to finding funding to complete the $2 million study required prior to the installation of a movable median barrier.
The bridge is popular with pedestrians and bicyclists as well as cars, and was built with walkways on either side of the six traffic lanes. Initially, they were separated by the traffic lanes by only a metal curb, but railings between the walkways and the traffic lanes were added in 2003, primarily as a measure to prevent runaway cyclists from falling into the roadway.
The main walkway is on the eastern side, and is open for use by both pedestrians and bicycles in the morning to mid-afternoon during weekdays (5 am to 3:30 pm), and to pedestrians only for the remaining daylight hours (until 6 pm, or 9 pm during DST). The eastern walkway is reserved for pedestrians on weekends (5 am to 6 pm, or 9 pm during DST), and is open exclusively to bicyclists in the evening and overnight, when it is closed to pedestrians. The western walkway is only open, and exclusively for bicyclists, during the hours when they are not allowed on the eastern walkway.
The speed limit on the Golden Gate Bridge was reduced from 55 mph (89 km/h) to 45 mph (72 km/h) on October 1, 1996.
some General Imformation
Carries : 6 lanes of US 101 / SR 1, pedestrians and bicycles
Crosses Golden Gate
Locale : San Francisco, California and Marin County, California
Maintained by : Golden Gate Bridge, Highway and Transportation District
Designer : Joseph Strauss, Irving Morrow, and Charles Ellis
Design Suspension, truss arch & truss causeways
Material Steel
Total length : 1.7 mi (2.7 km) or 8,981 ft (2,737.4 m)
Width : 90 ft (27.4 m)
Height : 746 ft (227.4 m)
Longest span : 4,200 ft (1,280.2 m)
Vertical clearance : 14 ft (4.3 m) at toll gates, higher truck loads possible
Clearance below :220 ft (67.1 m) at Tide
Construction begin : January 5, 1933; 78 years ago
Construction end : April 19, 1937
Opened : May 27, 1937; 74 years ago
Toll Cars : (southbound only)
$6.00 (cash), $5.00 (FasTrak), $3.00 (carpools during peak hours, FasTrak only)
Daily traffic : 118,000
No comments:
Post a Comment