Aon Center

This project will be renovated in 2021 and replaced by Aon Center (Renovation)

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Height: Occupied
328 m / 1,076 ft (est)
Height: Architectural
346.3 m / 1,136 ft
Aon Center Outline
  Height: To Tip
362.5 m / 1,189 ft (est)
Floors Above Ground
Floors Below Ground
Tower GFA
334,448 m² / 3,599,968 ft²
# of Parking Spaces


Official Name Aon Center
Other Names Amoco Building, Standard Oil Building
Structure Type Building
Status Completed
Country United States
City Chicago
Street Address & Map 200 East Randolph Drive
Postal Code 60601
Building Function office
Structural Material steel
Construction Start 1970
Completion 1973
Recladding 1992
Official Website Aon Center
Rankings Click arrows to view the next taller/shorter buildings
Global Ranking #67 Tallest in the World
Regional Ranking #9 Tallest in North America
National Ranking #9 Tallest in United States
City Ranking #3 Tallest in Chicago

Companies Involved

• Current 601 W Companies
• Past Amoco Corporation; Piedmont Office Realty Trust; The Blackstone Group L.P.
Design Edward Durell Stone & Associates; Perkins+Will
Structural Engineer
Design Perkins+Will
MEP Engineer
Design Cosentini Associates; Economy Mechanical Industries, Inc.
Main Contractor Turner Construction Company
Other Consultant
• Property Management JLL
• Wind RWDI
Material Supplier
• Cladding Alberto Bufalini Successori Ltd.; Cupples
• Elevator Otis Elevator Company
• Sealants Dow Corning Corporation

About Aon Center

Located in downtown Chicago overlooking Millennium and Grant Parks on the eastern edge of the Loop. The Aon Center is one of the “string of pearl” buildings that stand-out on Chicago’s skyline for their remarkable height. At the time of its completion, the building was only the sixth supertall tower ever constructed. Originally clad in Carrara marble, it was the tallest marble-clad building in the world until it was reclad in white granite due to safety concerns in the early 1990s.

Simple in design, the Aon Center appears monolithic, without any setbacks or adornments. The building’s shape and scale are reminiscent of New York’s original World Trade Center buildings, its architectural contemporaries. Similar to the World Trade Center towers, the Aon Center 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. The columns also house piping and utility lines, eliminating the need for interior column chases that so often deprive buildings of valuable office space. They also serve to emphasize the building’s height and augment its vertical prominence.

Despite the building’s imposing configuration, it is still well-integrated into its urban habitat. The Pedway, a series of underground pedestrian walkways, connects the Aon Center to numerous surrounding buildings throughout the loop. A plaza decorated with fountains and ample seating envelops the tower on all sides and provides an inviting place for pedestrians to congregate on a nice day. Taken together, the Aon Center’s quiet, dignified façade and its simplicity overall, make it a unique and memorable addition to the skyline.

CTBUH Initiatives

Top Company Rankings: The World’s 100 Tallest Buildings
13 Oct 2016 – CTBUH Research

Warm Weather Spaces Walking Tours 2015
17 Sep 2015 – Tour Report

Seven Cities Winter Spaces Walking Tour
29 Jan 2015 – Tour Report

Research Papers

The Global Tall Building Picture: Impact of 2019
Jan 2020 – CTBUH Journal 2020 Issue I

Dynamic Interrelationship between the Evolution of the Structural Systems and Façade Design in Tall Buildings
Mar 2018 – International Journal of High-Rise Buildings Volume 7 Number 1

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