Changes

[[Image:GoldenGateBridge02.jpg‎|thumb|300px|right|Golden Gate Bridge- more red than golden]]The '''Golden Gate Bridge''' is a suspension [[bridge]] that spans the bay between [[San Francisco]] and Marin County. A well-known landmark, the bridge was named after not for its color, but for the underlying "Golden Gate Strait", that is the entrance to the [[San Francisco Bay]] from the [[Pacific Ocean]].

The bridge is considered one of the very few human structures that ''enhance'' the physical beauty of nature, and was ranked as the fifth most popular American design in a poll of Americans.<ref>http://www.aia.org/release_020707_150Buildings</ref> Often fog engulfs it to create a spectacular visual effect.

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> Its primary span extends 4,200 feet, which was the longest in the world until the Verrazano-Narrows Bridge was completed in [[New York City]] in 1964.

generally 3 lanes open for traffic in each direction. <ref> http://goldengatebridge.org/tolls_traffic/ </ref> This bridge is part of the historic U.S. Highway 101, which runs the length of the Pacific Coast from southern California to northern Washington.

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>

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>

* 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> httphttps://www.pbs.org/wgbh/nova/bridge/meetsusp.html </ref> <ref> http://www.answers.com/topic/golden-gate-bridge </ref>

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>

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>

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

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 will switch 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 will be is now through use of the automated "Fastrak" system, .<ref>http://www.bayareafastrak.org/</ref> as As a consequence, 28 toll-takers will lose 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>

==ReferencesSee also==* [[San Francisco values|San Francisco]]

[[categoryCategory:San Francisco Bay Area]][[Category:San Francisco]][[Category:Northern California]][[Category:United States]]