Editing Gateway Arch (section)

===Physical characteristics===
[[File:Gateway Arch windows.jpg|thumb|The windows of the observation deck are located around the apex of the arch.]]
Both the width and height of the arch are {{convert|630|ft|m|0}}.<ref name="facts"/><ref name="Bryant"/> The arch is the tallest memorial in the United States<ref name="nhlsum">{{cite web |url=http://tps.cr.nps.gov/nhl/detail.cfm?ResourceId=2017&ResourceType=Structure |title=National Historic Landmarks Program: Gateway Arch |publisher=National Historic Landmarks Program |access-date=December 14, 2010 |archive-url=https://web.archive.org/web/20090804114340/http://tps.cr.nps.gov/nhl/detail.cfm?ResourceId=2017&ResourceType=Structure |archive-date=August 4, 2009 |url-status=dead }}</ref> and the tallest stainless steel monument in the world.<ref name="Cobb">{{cite book |last=Cobb |first=Harold M. |title=The History of Stainless Steel |url=https://books.google.com/books?id=E30rCBeM8nkC&q=%22tallest+monument%22&pg=PA308 |year=2010 |publisher=[[ASM International (society)|ASM International]] |location=Materials Park, OH |isbn=978-1-61503-010-1 |pages=170–174, 308 }}</ref>

The cross-sections of the arch's legs are [[equilateral triangle]]s, narrowing from {{convert|54|ft|m}} per side at the bases to {{convert|17|ft|m}} per side at the top.<ref name="PopSci">{{cite journal |url=https://books.google.com/books?id=mi0DAAAAMBAJ&pg=PA91 |title=St. Louis' Two-Legged Tower: Tallest U.S. Monument |last=Remsberg |first=Charles |date=April 1964 |journal=[[Popular Science]] |volume=184 |issue=4 |pages=91–94 |issn=0161-7370 }}</ref> Each wall consists of a [[stainless steel]] skin covering a sandwich of two carbon-steel walls with [[reinforced concrete]] in the middle from ground level to {{convert|300|ft|m}}, with [[carbon steel]] to the peak.<ref name="Brinkman"/><ref name="Mogin">{{cite news |url=http://thetartan.org/2006/10/30/scitech/htw |title=How Things Work: The Gateway Arch |last=Mogin |first=Sarah |date=October 30, 2006 |newspaper=[[The Tartan (Carnegie Mellon University)|The Tartan]] |access-date=December 14, 2010 |archive-url=https://web.archive.org/web/20101231061036/http://thetartan.org/2006/10/30/scitech/htw |archive-date=December 31, 2010 |url-status=dead }}</ref> The arch is hollow to accommodate a unique tram system that takes visitors to an observation deck at the top.<ref name="csmonitor"/>

The [[structural load]] is supported by a [[Stressed skin|stressed-skin]] design.<ref name="Freeman">{{cite news |url=https://pqasb.pqarchiver.com/csmonitor_historic/access/219784512.html?dids=219784512:219784512&FMT=ABS&FMTS=ABS:AI |title=St. Louis Gateway Arch—a sweeping view |last=Freeman |first=Mary T. |date=November 4, 1967 |newspaper=[[The Christian Science Monitor]] |page=15 |access-date=December 17, 2010 |archive-url=https://www.webcitation.org/61hbjIgRp?url=http://hn.bigchalk.com/pqdocs/share4/pqimage/hnirs101v/201109141827/00611/32220/out.pdf |archive-date=September 14, 2011 |url-status=dead }}</ref> Each leg is embedded in {{convert|25980|ST|MT}} of concrete {{convert|44|ft|m}} thick<ref name="Bryant">{{cite news |url=https://www.chicagotribune.com/1985/10/28/gateway-arch-marks-20-years-over-st-louis/ |title=Gateway Arch Marks 20 Years Over St. Louis |last=Bryant |first=Tim |date=October 28, 1985 |newspaper=Chicago Tribune |agency=[[United Press International]] |page=12 |access-date=January 7, 2011 |issn=1085-6706 |archive-url=https://web.archive.org/web/20121007045359/http://articles.chicagotribune.com/1985-10-28/news/8503130852_1_eero-saarinen-jefferson-national-expansion-memorial-leg |archive-date=October 7, 2012 |url-status=live }}</ref> and {{convert|60|ft|m}} deep.<ref name="Sutton">{{cite news |url=https://pqasb.pqarchiver.com/chicagotribune/access/629600072.html?dids=629600072:629600072&FMT=ABS&FMTS=ABS:AI |title=Spectacle in Steel: St. Louis' Giant Gateway Arch |last=Sutton |first=Horace |date=December 5, 1965 |newspaper=Chicago Tribune |page=J21 |access-date=December 22, 2010 |archive-url=https://www.webcitation.org/61hc1jmrY?url=http://hn.bigchalk.com/pqdocs/share4/pqimage/hnirs101v/201109141831/32392/32213/out.pdf |archive-date=September 14, 2011 |url-status=dead }}</ref> {{convert|20|ft|m|spell=In}} of the foundation is in [[bedrock]].<ref name="Sutton"/> The arch is resistant to earthquakes<ref name="National Parks 1998">{{cite journal |url=https://books.google.com/books?id=KDq3pMiK03sC&pg=PA35 |title=On the Trail of Discovery |last=La Pierre |first=Yvette |journal=[[National Parks (magazine)|National Parks]] |date=July–August 1998 |volume=72 |issue=7–8 |publisher=[[National Parks Conservation Association]] |issn=0276-8186 }}</ref> and is designed to sway up to {{convert|18|in|cm}} in either direction,<ref>{{Cite web |url=http://www.gatewayarch.com/about/history/arch-faqs-facts.aspx |title=Plan Your Visit |access-date=April 17, 2016 |archive-date=April 18, 2016 |archive-url=https://web.archive.org/web/20160418032150/http://www.gatewayarch.com/about/history/arch-faqs-facts.aspx |url-status=dead }}</ref> while withstanding winds up to {{convert|150|mph|km/h}}.<ref name="Post-Dispatch"/> The structure weighs {{convert|42878|ST|MT}}, of which concrete composes {{convert|25980|ST|MT}}; structural steel interior, {{convert|2157|ST|MT}}; and the 6.3mm thick grade 304 stainless steel panels that cover the exterior of the arch, {{convert|886|ST|MT}}.<ref name="Offer"/><ref>{{cite web |url=https://www.doublestonesteel.com/blog/design/the-history-of-the-gateway-arch-st-louis-also-known-as-the-st-louis-arch-designed-by-eero-saarinen-and-completed-in-1965/#:~:text=The%20Gateway%20Arch%20is%20the%20largest%20stainless%20steel%20building%20in,how%20durable%20304%20can%20be. |title=The Gateway Arch, St Louis |date=July 6, 2015 }}</ref> This amount of stainless steel is the most used in any one project in history.<ref name="Cobb"/><ref name="Post-Dispatch"/>