Editing Golden Gate Bridge (section)

==Structural specifications==
[[File:GG-bridge-cable.jpg|thumb|upright|On the south side of the bridge a {{convert|36.5|in|cm|adj=mid|-wide}} cross-section of the cable, containing 27,572 wires, is on display.]]

Until 1964, the Golden Gate Bridge had the longest suspension bridge main span in the world, at {{convert|4,200|ft|m|sigfig=3}}. Since 1964 its main span length has been [[List of longest suspension bridge spans|surpassed by twenty bridges]]; it now has the second-longest main span in the [[Americas]], after the [[Verrazzano-Narrows Bridge]] in New York City. The total length of the Golden Gate Bridge from [[abutment]] to abutment is {{convert|8,981|ft|m}}.<ref name = "factsGGBDesign">{{cite web|title=Bridge Design and Construction Statistics|url=http://goldengatebridge.org/research/factsGGBDesign.php|website=goldengatebridge.org|publisher=Golden Gate Bridge, Highway and Transportation District|access-date=November 27, 2017|language=en|archive-date=March 4, 2011|archive-url=https://web.archive.org/web/20110304130356/http://www.goldengatebridge.org/research/factsGGBDesign.php|url-status=dead}}</ref>

The Golden Gate Bridge's clearance above high water averages {{convert|220|ft|m}} while its towers, at {{convert|746|ft|m}} above the water,<ref name = "factsGGBDesign"/> were the world's tallest on a suspension bridge until 1993 when it was surpassed by the [[Mezcala Bridge]], in Mexico.

The weight of the roadway is hung from 250 pairs of vertical suspender ropes, which are attached to two main [[Wire rope|cables]]. The main cables pass over the two main towers and are fixed in concrete at each end. Each cable is made of 27,572 strands of wire. The total length of galvanized steel [[wire]] used to fabricate both main cables is estimated to be {{convert|80,000|mi|km}}.<ref name = "factsGGBDesign"/> Each of the bridge's two towers has approximately 600,000 [[rivet]]s.<ref>[http://goldengatebridge.org/research/facts.php#RivetsinTower "Frequently Asked Questions about the Golden Gate Bridge: How many rivets are in each tower of the Golden Gate Bridge?"] {{Webarchive|url=https://web.archive.org/web/20150810050111/http://goldengatebridge.org/research/facts.php#RivetsinTower |date=August 10, 2015 }}. ''goldengatebridge.org''. Golden Gate Bridge, Highway and Transportation District. Retrieved November 5, 2018.</ref>

In the 1960s, when the [[Bay Area Rapid Transit]] system (BART) was being planned, the engineering community had conflicting opinions about the feasibility of running train tracks north to Marin County over the bridge.<ref>{{cite web |title=A History of BART |url=https://www.bart.gov/about/history |access-date=November 5, 2018}}</ref> In June 1961, consultants hired by BART completed a study that determined the bridge's suspension section was capable of supporting service on a new lower deck.<ref name="1961Report">{{cite web |title=Rapid Transit for the San Francisco Bay Area |url=http://libraryarchives.metro.net/DPGTL/bart/1961-parsons-engineering-report-to-sf-bart-district.pdf |archive-url=https://web.archive.org/web/20160917014219/http://libraryarchives.metro.net/DPGTL/bart/1961-parsons-engineering-report-to-sf-bart-district.pdf |archive-date=September 17, 2016 |url-status=live |website=LA Metro Library |publisher=Parsons Brinckerhoff / Tudor / Bechtel |access-date=July 21, 2018}}</ref> In July 1961, one of the bridge's consulting engineers, Clifford Paine, disagreed with their conclusion.<ref>{{Cite web|url=https://www.marinij.com/2010/08/07/did-marin-lose-out-on-bart/|title=Did Marin lose out on BART?|last=Prado|first=Mark|date=August 7, 2010|website=Marin Independent Journal|access-date=May 3, 2019}}</ref> In January 1962, due to more conflicting reports on feasibility, the bridge's board of directors appointed an engineering review board to analyze all the reports. The review board's report, released in April 1962, concluded that running BART on the bridge was not advisable.<ref>{{cite report |last1=Ammann |first1=Othmar H. |author-link1=Othmar Ammann |last2=Masters |first2=Frank M. |last3=Newmark |first3=Nathan M. |title=Report on Proposed Installation of Rapid Transit Trains on Golden Gate Bridge |date=April 1962 |publisher=Golden Gate Bridge And Highway District |page= 8 |url=https://catalog.hathitrust.org/Record/101668914 }}</ref>