View source for Aon Center (Chicago)

{{Short description|Skyscraper in Chicago, Illinois}}
{{Use American English|date=January 2023}}
{{Use mdy dates|date=January 2023}}
{{Infobox building
| name             = Aon Center
| status           = Completed
| former_names     = {{ubl|Amoco Building|Standard Oil Building}}
| architectural_style = [[Modern architecture|Modern]]
| logo             = Aon Center (Chicago) logo.png
| logo_size        = 210
| image            = Aon Center 2014.jpg
| image_size       = 250
| caption          = The Aon Center in 2014 
| location         = 200 E. [[Randolph Street (Chicago)|Randolph St.]]<br />[[Chicago]], [[Illinois]] 60601<br />United States
| coordinates      = {{coord|41|53|07|N|87|37|17|W|region:US-IL|display=inline,title}}
| start_date       = 1970
| architect        = [[Edward Durell Stone]]<ref name=skyscraperCenter/>
| owner            = [[Mark Karasick]]<br>Victor Gerstein<ref name="Owners">{{cite news |url=https://commercialobserver.com/2018/06/j-p-morgan-brookfield-provide-678m-financing-package-for-chicagos-aon-building/ |title=J.P. Morgan, Brookfield Provide $678M Financing Package for Chicago's Aon Center |journal=Commercial Observer |date=June 8, 2018 |first1=Cathy |last1=Cunningham |first2=Matt |last2=Grossman}}</ref>
| cost             = {{US$|link=yes}}120 million
| floor_area       = {{convert|3,599,968|sqft|m2|0|abbr=on|disp=flip}}<ref name=skyscraperCenter/>
| top_floor        = {{convert|328|m|ft|abbr=on}}<ref name=skyscraperCenter/>
| floor_count      = 83 above ground<ref name=skyscraperCenter>{{cite web|url=http://skyscrapercenter.com/chicago/aon-center/ |title=The Skyscraper Center: Aon Center |website=Council on Tall Buildings and Urban Habitat |url-status=dead |archive-url=https://web.archive.org/web/20140808052100/http://skyscrapercenter.com/chicago/aon-center/ |archive-date=August 8, 2014}}</ref><br />5 below ground
| references       = <ref name=skyscraperCenter/>
| map_type         = Chicago#Illinois#USA
| building_type    = [[Office building]]
| architectural    = {{convert|346.3|m|ft|abbr=on}}<ref name=skyscraperCenter/>
| tip              = {{convert|362.5|m|ft|abbr=on}}<ref name=skyscraperCenter/>
| elevator_count   = 50, made by the [[Otis Elevator Company]]
| main_contractor  = [[Turner Construction]]<ref name=skyscraperCenter/>
| opening          = 1973
| developer        = [[Standard Oil of Indiana]]
| website          = {{URL|https://www.aoncenter.info/|aoncenter.info}}
}}

The '''Aon Center''' (200 East [[Randolph Street (Chicago)|Randolph Street]], formerly '''Amoco Building''')<ref>{{cite news| url=http://docs.newsbank.com/openurl?ctx_ver=z39.88-2004&rft_id=info:sid/iw.newsbank.com:NewsBank:CSTB&rft_val_format=info:ofi/fmt:kev:mtx:ctx&rft_dat=0F968E80C195CF74&svc_dat=InfoWeb:aggregated5&req_dat=AA98CDC331574F0ABEAFF732B33DC0B2| title=New owner expected for Aon Center| access-date=September 18, 2008| date=February 21, 2003|via=Newsbank| newspaper=[[Chicago Sun-Times]]| last=Roeder| first=David}}</ref> is a modern supertall [[skyscraper]] located in the Northeast corner of the [[Chicago Loop]], Chicago, Illinois, United States. It was designed by architect firms [[Edward Durell Stone]] and The [[Perkins and Will]] partnership, and completed in 1973<ref>{{cite book| title=The Sky's the Limit: A Century of Chicago Skyscrapers| page=[https://archive.org/details/skyslimitcentury0000unse/page/219 219]| location=New York| publisher=Rizzoli| year=1990| editor-last=Saliga| editor-first=Pauline| isbn=978-0847811793| url=https://archive.org/details/skyslimitcentury0000unse/page/219}}</ref> as the '''Standard Oil Building''' (nicknamed "Big Stan").<ref name="emporis">{{cite web| website=Emporis| title=Aon Center, Chicago| url=http://www.emporis.com/en/wm/bu/?id=aoncenter-chicago-il-usa| archive-url=https://web.archive.org/web/20061207041041/http://www.emporis.com/en/wm/bu/?id=aoncenter-chicago-il-usa| url-status=usurped| archive-date=December 7, 2006| access-date=April 23, 2008}}</ref> With 83 floors and a height of 1,136&nbsp;feet (346&nbsp;m), it is the [[List of tallest buildings in Chicago|fourth-tallest building in Chicago]],<ref name="skyscraperCenter" /> surpassed in height by the [[Willis Tower]], [[Trump International Hotel and Tower (Chicago)|Trump International Hotel and Tower]], and [[St. Regis Chicago|St.{{nbsp}}Regis Chicago]].

The building is managed by [[JLL (company)|JLL]], which is also headquartered in the building. Aon Center houses the headquarters of [[Aon (company)|Aon]], [[Blue Cross Blue Shield Association]], and [[Kraft Heinz]] (BCBS and Kraft Heinz each have a second headquarters, located in [[Washington, D.C.|Washington D.C.]] and [[Pittsburgh]] respectively);<ref>{{Cite web |title=Blue Cross and Blue Shield Customer Service – Contact Us {{!}} bcbs.com |url=https://www.bcbs.com/customer-service-contact-us |access-date=2024-10-19 |website=Blue Cross Blue Shield Association |language=en}}</ref> the building formerly served as the world headquarters of [[Amoco]] prior to its merger into [[BP]].<ref>{{cite news |first1=Nathalie |last1=Tadena |first2=Jason |last2=Dean |first3=Leslie |last3=Scism |date=January 14, 2012 |url=https://www.wsj.com/articles/SB10001424052970204542404577158633936346056 |access-date=January 20, 2020 |title=Aon Shifts Headquarters to London |newspaper=[[The Wall Street Journal]] |url-access=subscription |archive-url=https://web.archive.org/web/20170831134316/https://www.wsj.com/articles/SB10001424052970204542404577158633936346056 |archive-date=August 31, 2017 |url-status=dead}}</ref><ref>"[https://web.archive.org/web/19980212072931/http://www.amoco.com/contacts/index.html Contacts]". [[Amoco]]. February 12, 1998. Retrieved on March 31, 2010.</ref><ref>{{cite news| title=Kraft Heinz eliminated another 1,000 jobs in 2016| url=http://www.chicagotribune.com/business/ct-kraft-heinz-job-cuts-20170223-story.html| first=Lisa| last=Du| date=February 23, 2017| newspaper=[[Chicago Tribune]]| agency=[[Bloomberg News]]}}</ref><ref>{{cite news| title=Kraft Heinz preps HQ move into Chicago|url=https://www.bizjournals.com/chicago/news/2015/07/16/kraft-heinz-preps-hq-move-into-chicago.html| date=July 15, 2015| newspaper=[[American City Business Journals|Chicago Business Journal]]| access-date=January 20, 2020}}</ref>

The building was briefly the tallest in Chicago, but was soon surpassed by the [[Willis Tower|Sears Tower]]. It was the fourth-tallest building in the world at the time of its completion.

==History==

===Construction===
[[File: Chicago - Buckingham Fountain (4284462009).jpg|thumb|View from [[Buckingham Fountain]] of the building while it was under-construction|left]]

The Standard Oil Building was constructed as the headquarters of the [[Amoco|Standard Oil Company of Indiana]]. Standard's previous home had been 910 S. Michigan Avenue. This building was constructed in 1911 by the Karpen Brothers Furniture Company and was purchased by Standard in 1927. When the new Standard Oil Building was completed in 1973, it was the tallest completed building in Chicago and the fourth-tallest in the world, earning it the nickname "Big Stan".<ref name="gss">{{cite web| website=Glass Steel and Stone| title=Aon Center| url=http://www.glasssteelandstone.com/BuildingDetail/625.php| access-date=September 25, 2007| archive-url=https://web.archive.org/web/20070826091210/http://www.glasssteelandstone.com/BuildingDetail/625.php| archive-date=August 26, 2007| url-status=usurped}}</ref> In 1974, the taller Sears Tower (now Willis Tower) in Chicago surpassed it as the tallest completed building in Chicago (the Sears Tower was also the tallest in the world). However, the Sears Tower had already been [[topped out]] in May 1973.<ref name="SearsTopping"/><ref name="archiseek"/> When the Aon Center opened as the fourth-tallest completed building in the world, it was only exceeded in height by the twin towers of the original [[World Trade Center (1973–2001)|World Trade Center]] and the [[Empire State Building]] in [[New York City]].<ref name="SearsTopping">{{cite web |last1=Nelson |first1=Bryce |title=Sears 'Topping Out' Puts Chicago On Top |url=https://www.newspapers.com/image/265469018/ |website=Newspapers.com |access-date=October 9, 2022 |language=en |date=May 7, 1973}}</ref> Originally clad in [[marble]], the Aon Center was also the tallest marble-clad building in the world.<ref name="archiseek">{{cite web |title=1973 – Aon Center, Chicago, Illinois |url=https://www.archiseek.com/2009/1973-aon-center-chicago-illinois/ |website=Archiseek - Irish Architecture |access-date=October 9, 2022 |date=September 20, 2009}}</ref>

The building employs a tubular steel-framed structural system with V-shaped perimeter columns to resist [[earthquakes]], reduce sway, minimize column bending, and maximize column-free space.  This construction method was also used for the original World Trade Center twin towers in [[New York City]].

===Refacing===
[[File:Aon Center during resurfacing with temporary work elevators in its corners (22427576248) (1).jpg|thumb|Aon Center in the 1990s during its refacing, with temporary work [[elevators]] erected in the building's corners|left]]

When completed, it was the world's tallest [[marble]]-clad building, sheathed entirely with 43,000 slabs of Italian [[Carrara marble]].  The marble used was thinner than previously attempted in cladding a building, which soon proved to be a mistake.  On December 25, 1973, during construction a 350-pound marble slab detached from the façade and penetrated the roof of the nearby [[One Prudential Plaza|Prudential Center]].<ref>Chicago Tribune, December 26, 1973</ref>  In 1985, inspection found numerous cracks and bowing in the marble cladding of the building.  To alleviate the problem, stainless steel straps were added to hold the marble in place.<ref name="gss" />  Later, from 1990 to 1992, the entire building was refaced with [[Mount Airy, North Carolina|Mount Airy]] white [[granite]] at an estimated cost of over $80 million.<ref name="emporis" /><ref name="globe">{{cite news |last=McMillan |first=Greg |publication-date=June 12, 2007 |title=Two buildings, two cities, one problem |periodical=[[The Globe and Mail]] |publication-place=Toronto |url=https://www.theglobeandmail.com/report-on-business/two-buildings-two-cities-one-problem/article17996906/ |access-date=September 25, 2007}}</ref> Amoco was reluctant to divulge the actual amount, but it was well over half the original price of the building, without adjustment for inflation. Two-thirds of the discarded marble was crushed and used as landscaping decoration at Amoco's refinery in [[Whiting, Indiana]], one-sixth was donated to [[Governors State University]], in [[University Park, Illinois|University Park]], and one-sixth donated to Regalo, a division of Lashcon Inc.  Under a grant from the Illinois Department of Rehabilitative Services, Regalo's 25 handicapped workers carved the discarded marble into a variety of specialty items such as corporate gifts and mementos including desk clocks and pen holders.<ref name="emporis" /><ref name="UIC OSWM">{{cite web |url=http://www.p2pays.org/ref/24/23685.pdf |archive-url=https://ghostarchive.org/archive/20221009/http://www.p2pays.org/ref/24/23685.pdf |archive-date=October 9, 2022 |url-status=live |title=Construction and Demolition Waste: Generation, Regulation, Practices, Processing, and Policies |first1=Stephen D. |last1=Cosper |author2=William H. Hallenbeck |author3=Gary R. Brenniman |date=January 1993 |publisher=University of Illinois at Chicago, Office of Solid Waste Management |access-date=March 26, 2010 | page=31}}</ref>

===Designation===
The Standard Oil Building was renamed the Amoco Building when the company changed names in 1985.  In 1998, Amoco sold the building to [[The Blackstone Group]] for an undisclosed amount, estimated to be between $430 and $440 million.<ref name="emporis" /><ref name="gss" /> It was renamed as the Aon Center on December 30, 1999, although [[Aon (company)|Aon]] would not become the building's primary tenant until September 2001.<ref>{{cite web| title=AON Center Chicago: Skyscraper Architecture| url=https://www.e-architect.co.uk/chicago/aon-center| first=David| last=McManus| date=July 12, 2018| website=e-Architect| access-date=January 20, 2020}}</ref>  In May 2003, Wells Real Estate Investment Trust, Inc. acquired the building for between $465 and $475 million.<ref name="emporis" /><ref>{{cite web |website=Miller Cicero, LLC |title=Trophy Building Sale Sets New Record |date=October 7, 2003 |url=http://www.millercicero.com/press/files-view.php?ViewNode=1066154585cVxrI |access-date=September 25, 2007 |archive-url=https://web.archive.org/web/20070518025208/http://www.millercicero.com/press/files-view.php?ViewNode=1066154585cVxrI  |archive-date=May 18, 2007 |url-status=dead}}</ref> On August 10, 2007, Wells Real Estate Investment Trust, Inc. changed its name to Piedmont Office Realty Trust, Inc.)<ref>{{cite web |website=Piedmont Office Realty Trust, Inc. |title=Wells REIT Changes Name to Piedmont Office Realty Trust |url=http://www.piedmontreit.com/cms/content/view/139/63 |access-date=August 10, 2007 |url-status=dead |archive-url=https://web.archive.org/web/20080610020230/http://www.piedmontreit.com/cms/content/view/139/63 |archive-date=June 10, 2008}}</ref>

Real estate investors Mark Karasick and Victor Gerstein acquired the building from Piedmont in 2015 for $713 million.<ref name="Owners"/>

===Planned observation deck===
{{update section|date=April 2024}}
On May 14, 2018, the building's owners unveiled a $185 million proposal for an observatory featuring a thrill ride on the roof called the Sky Summit, the world's tallest exterior elevator, and new entrance pavilion. The observatory was supposed to be completed in 2022, but the [[COVID-19 pandemic]] had been announced to have delayed construction plans by about a year.<ref>{{cite news| title=Aon Center's planned observation deck, Chicago's third, could create competition for tourist dollars| url=http://www.chicagotribune.com/business/ct-biz-chicago-observation-decks-20180511-story.html| first1=Ally| last1=Marotti| first2=Blair| last2=Kamin| date=May 15, 2018| newspaper=Chicago Tribune| access-date=January 20, 2020}}</ref><ref>{{Cite web|title=Construction halted for Aon Center observatory in Chicago due to coronavirus pandemic|url=https://www.usatoday.com/story/travel/news/2020/06/29/coronavirus-construction-halted-aon-center-observatory-chicago/3277266001/|access-date=November 28, 2020|website=USA TODAY|language=en-US}}</ref>

==Position in Chicago's skyline (2006)==
{{Chicago skyline}}

==Gallery==
<gallery mode="packed" heights="200">
File:20220525 Lakeshore East from Cascade.jpg|From the east
File:Aon center.JPG|From the southwest
File:2004-07-14 1880x2820 chicago aon looking up.jpg|Looking up the building from the ground
File:Skyscrapers in Chicago, including the AON Center, Chicago, IL 11-22-15.jpg|Looking from the North, with [[Aqua (Chicago)|Aqua]] visible
File:Aon Center 2.jpg|From the base
</gallery>

==See also==
{{Portal|Chicago|Illinois}}
* [[Aon Center (Los Angeles)]]
* [[First Canadian Place]] – a similar building from the same architect
* [[List of buildings]]
* [[List of skyscrapers]]
* [[List of tallest buildings and structures in the world]]
* [[List of tallest buildings in Chicago]]
* [[List of tallest buildings in the United States]]
* [[List of tallest freestanding structures in the world]]
* [[List of tallest freestanding steel structures]]

== References ==
{{Reflist}}

==External links==
{{commons category}}
* [https://web.archive.org/web/20140808052100/http://skyscrapercenter.com/chicago/aon-center/ Aon Center] on [[CTBUH]] Skyscraper Center
* [http://www.buzzfile.com/Lists/Companies-located-at-200-E-Randolph-St,-Chicago,-IL,-60601 List of tenants at the Aon Center] - Companies located at 200 East Randolph Street, Chicago IL

{{s-start}}
{{s-bef|rows=2|before=[[John Hancock Center]]}}
{{s-ttl|title=[[List of tallest buildings in Chicago|Tallest building in Chicago]]|years=1972–1973<br /><small>1,136&nbsp;ft</small>}}
{{s-aft|rows=2|after=[[Willis Tower]]}}
{{s-break}}
{{s-ttl|title=Tallest building in the United States outside of New York City|years=1972–1973<br /><small>1,136&nbsp;ft</small>}}
{{s-end}}
{{Chicago Loop}}
{{Supertall skyscrapers | current}}
{{Chicago Skyscrapers}}
{{Chicago}}
{{BP}}
{{Buildings in Chicago timeline}}

[[Category:Skyscraper office buildings in Chicago]]
[[Category:Insurance company headquarters in the United States]]
[[Category:BP buildings and structures]]
[[Category:Office buildings completed in 1973]]
[[Category:Edward Durell Stone buildings]]
[[Category:JLL (company)]]
[[Category:International style architecture in Illinois]]
[[Category:Modernist architecture in Illinois]]
[[Category:1973 establishments in Illinois]]