Changes

</blockquote>

</blockquote>

The bridge is built of fabricated [[steel]], and is painted with an orange color that protects the Bridge's steel components from rust and corrosion caused by the high salt content in the air from the Pacific Ocean. <ref> http://goldengatebridge.org/ </ref> The construction of the bridge took four years to complete (Jan 1933 - May 1937) at a cost of $35 million dollars. <ref> http://www.inetours.com/Pages/SFNbrhds/Golden_Gate_Bridge.html </ref>

The bridge is built of fabricated [[steel]], and is painted with an orange color that protects the Bridge's steel components from rust and corrosion caused by the high salt content in the air from the Pacific Ocean.<ref>http://goldengatebridge.org/</ref> The construction of the bridge took four years to complete (Jan 1933 - May 1937) at a cost of $35 million dollars.<ref>http://www.inetours.com/Pages/SFNbrhds/Golden_Gate_Bridge.html</ref>

The 6 traffic lanes of the bridge are located on one level, and have  

The 6 traffic lanes of the bridge are located on one level, and have  

northbound traffic. In the evenings the configuration is reversed to  

northbound traffic. In the evenings the configuration is reversed to  

allow for heavier traffic leaving the city. On weekends there are  

allow for heavier traffic leaving the city. On weekends there are  

generally 3 lanes open for traffic in each direction. <ref>  

generally 3 lanes open for traffic in each direction.<ref>

http://goldengatebridge.org/tolls_traffic/ </ref>

http://goldengatebridge.org/tolls_traffic/</ref>

The engineering team was headed up by Chief Engineer Joseph Strauss  

The engineering team was headed up by Chief Engineer Joseph Strauss  

who initially designed the bridge. Irving Morrow was the architect   

who initially designed the bridge. Irving Morrow was the architect   

responsible for the Art Deco designs, and engineer Charles Alton Ellis and bridge designer Leon Moisseiff collaborated on the mathematics involved in building the bridge. In 1955 a statue of Joseph Strauss was placed in a landing near the bridge to recognize his contributions. <ref> http://www.americanscientist.org/ </ref>  

responsible for the Art Deco designs, and engineer Charles Alton Ellis and bridge designer Leon Moisseiff collaborated on the mathematics involved in building the bridge. In 1955 a statue of Joseph Strauss was placed in a landing near the bridge to recognize his contributions.<ref>http://www.americanscientist.org/</ref>  

== Suspension Bridges ==

== Suspension Bridges ==

The Golden Gate Bridge, at 4,200 feet, (1,280 meters) long was the  

The Golden Gate Bridge, at 4,200 feet, (1,280 meters) long was the  

longest suspension bridge in the world from the time it opened in 1937 until [[New York City]]'s Verrazano Narrows Bridge was opened on November 21, 1964. <ref> http://www.answers.com/topic/golden-gate-bridge </ref>

longest suspension bridge in the world from the time it opened in 1937 until [[New York City]]'s Verrazano Narrows Bridge was opened on November 21, 1964.<ref>http://www.answers.com/topic/golden-gate-bridge</ref>

There are currently 6 other suspension bridges that are longer than the Golden Gate:

There are currently 6 other suspension bridges that are longer than the Golden Gate:

* Tsing Ma Bridge, China 4,518 feet (1,377 meters), built in 1997.  

* Tsing Ma Bridge, China 4,518 feet (1,377 meters), built in 1997.  

* Verrazano Narrows Bridge, New York 4,260 feet (1,299 meters),  built in 1964 <ref> http://goldengatebridge.org/research/facts.php </ref>

* Verrazano Narrows Bridge, New York 4,260 feet (1,299 meters),  built in 1964 <ref>http://goldengatebridge.org/research/facts.php</ref>

The suspension design of the bridge was chosen to help it withstand an earthquake. A suspension bridge suspends the roadway from the main cables, which extend from one end of the bridge to the other. These cables rest on top of high towers and are secured at each end by anchorages. The towers enable the main cables to be draped over long distances. Most of the weight of the bridge is carried by the cables to the anchorages, which are imbedded in either solid rock or massive concrete blocks. Inside the anchorages, the cables are spread over a large area to evenly distribute the load and to prevent the cables from breaking free. <ref> http://www.pbs.org/wgbh/nova/bridge/meetsusp.html </ref> <ref> http://www.answers.com/topic/golden-gate-bridge </ref>

The suspension design of the bridge was chosen to help it withstand an earthquake. A suspension bridge suspends the roadway from the main cables, which extend from one end of the bridge to the other. These cables rest on top of high towers and are secured at each end by anchorages. The towers enable the main cables to be draped over long distances. Most of the weight of the bridge is carried by the cables to the anchorages, which are imbedded in either solid rock or massive concrete blocks. Inside the anchorages, the cables are spread over a large area to evenly distribute the load and to prevent the cables from breaking free.<ref>http://www.pbs.org/wgbh/nova/bridge/meetsusp.html</ref><ref>http://www.answers.com/topic/golden-gate-bridge</ref>

== Seismic Retrofit ==

== Seismic Retrofit ==

In October of 1989 when the [[Loma Prieta Earthquake]], a 7.1 richter earthquake hit the Bay Area, the nearby [[Oakland-San Francisco Bay Bridge]], (built from 1933 - 1936), was unable to withstand the tremors, causing the upper deck of the bridge to fall unto the lower level. <ref>  

In October 1989 when the [[Loma Prieta Earthquake]], a 7.1 richter earthquake hit the Bay Area, the nearby [[Oakland-San Francisco Bay Bridge]], (built from 1933 - 1936), was unable to withstand the tremors, causing the upper deck of the bridge to fall unto the lower level.<ref>

http://www.answers.com/topic/san-francisco-oakland-bay-bridge  

http://www.answers.com/topic/san-francisco-oakland-bay-bridge  

</ref>

</ref>

part of the bridge. The construction is planned in 4 phases, each  

part of the bridge. The construction is planned in 4 phases, each  

addressing separate areas of the bridge. The areas to be worked on  

addressing separate areas of the bridge. The areas to be worked on  

include the structural steel, the approach viaducts, the concrete piers, pylons and anchorage housings. The main cable saddles that run to the tops of the towers will be reinforced, and the steel tower shafts and the struts that connect them will be overhauled. <ref> http://www.infoplease.com/spot/goldengate.html </ref>

include the structural steel, the approach viaducts, the concrete piers, pylons and anchorage housings. The main cable saddles that run to the tops of the towers will be reinforced, and the steel tower shafts and the struts that connect them will be overhauled.<ref>http://www.infoplease.com/spot/goldengate.html</ref>

Construction began in August 1997 and is tentatively scheduled to be  

Construction began in August 1997 and is tentatively scheduled to be  

completed by 2014. The retrofit project is currently (as of March 2013) in Phase 3, the final phase of construction. <ref> http://goldengatebridge.org/projects/retrofit.php</ref>. The total cost of the retrofit is estimated to be  

completed by 2014. The retrofit project is currently (as of March 2013) in Phase 3, the final phase of construction.<ref>http://goldengatebridge.org/projects/retrofit.php</ref> The total cost of the retrofit is estimated to be  

around $405 million dollars. Once completed, the bridge should be able to withstand an 8.3 magnitude earthquake. <ref> http://goldengate.org/news/bridge/GGBSeismicStatusApr2006.php  

around $405 million dollars. Once completed, the bridge should be able to withstand an 8.3 magnitude earthquake.<ref>http://goldengate.org/news/bridge/GGBSeismicStatusApr2006.php  

</ref>

</ref>

==Tolls==

==Tolls==

The bridge district charges a $5 toll for vehicles approaching from the North (southbound, entering San Francisco from Marin) and is free for vehicles travelling the opposite direction (leaving San Francisco). Pedestrians and bicyclists may travel across the bridge using the Pedestrian walkway free of charge. <ref> http://goldengatebridge.org </ref> The Golden Gate bridge changed to an all-electronic toll-taking system on March 27, 2013. <ref>http://www.pressdemocrat.com/article/20130309/ARTICLES/130309557</ref> The main payment for bridge tolls is now through use of the automated "Fastrak" system. <ref>http://www.bayareafastrak.org/</ref> As a consequence, 28 toll-takers lost their jobs, and there are no longer any traffic lanes with human toll takers. <ref>http://www.sfexaminer.com/local/transportation/2013/03/golden-gate-bridge-debut-all-electronic-tolling-starting-march-27</ref>

The bridge district charges a $5 toll for vehicles approaching from the North (southbound, entering San Francisco from Marin) and is free for vehicles travelling the opposite direction (leaving San Francisco). Pedestrians and bicyclists may travel across the bridge using the Pedestrian walkway free of charge.<ref>http://goldengatebridge.org</ref> The Golden Gate bridge changed to an all-electronic toll-taking system on March 27, 2013.<ref>http://www.pressdemocrat.com/article/20130309/ARTICLES/130309557</ref> The main payment for bridge tolls is now through use of the automated "Fastrak" system.<ref>http://www.bayareafastrak.org/</ref> As a consequence, 28 toll-takers lost their jobs, and there are no longer any traffic lanes with human toll takers.<ref>http://www.sfexaminer.com/local/transportation/2013/03/golden-gate-bridge-debut-all-electronic-tolling-starting-march-27</ref>

==See Also==

==See also==

* [[San Francisco values|San Francisco]]

* [[San Francisco values|San Francisco]]

<references/>

<references/>

[[Category : Bridges]]

[[Category:Bridges]]

[[Category : San Francisco Bay Area]]

[[Category:San Francisco Bay Area]]

[[Category : San Francisco]]

[[Category:San Francisco]]

[[Category : Northern California]]

[[Category:Northern California]]

[[category : United States]]

[[Category:United States]]

[[Category : Tourist Attractions]]

[[Category:Tourist Attractions]]

[[Category : California]]

[[Category:California]]

[[Category : Famous Landmarks]]

[[Category:Famous Landmarks]]