Aon Center
Chicago

This project is a renovation and will replace Aon Center (Previous)

Height 349.9 m / 1148 ft
Floors 84
Official Name

The current legal building name.

Aon Center
Other Names

Other names the building has commonly been known as, including former names, common informal names, local names, etc.

Amoco Building, Standard Oil Building
Type

CTBUH collects data on two major types of tall structures: 'Buildings' and 'Telecommunications / Observation Towers.' A 'Building' is a structure where at least 50% of the height is occupied by usable floor area. A 'Telecommunications / Observation Tower' is a structure where less than 50% of the structure's height is occupied by usable floor area. Only 'Buildings' are eligible for the CTBUH 'Tallest Buildings' lists.

Building
Status
Completed
Architecturally Topped Out
Structurally Topped Out
Under Construction
Proposed
On Hold
Never Completed
Vision
Competition Entry
Canceled
Proposed Renovation
Under Renovation
Renovated
Under Demolition
Demolished
Proposed Renovation
Country

The CTBUH follows the United Nations's definition of Country, and thus uses the lists and codes established by that organization.

City

The CTBUH follows the United Nations's definition of City, and thus uses the lists and codes established by that organization.

Postal Code
60601
Function

A single-function tall building is defined as one where 85% or more of its usable floor area is dedicated to a single usage. Thus a building with 90% office floor area would be said to be an "office" building, irrespective of other minor functions it may also contain.

A mixed-use tall building contains two or more functions (or uses), where each of the functions occupy a significant proportion of the tower's total space. Support areas such as car parks and mechanical plant space do not constitute mixed-use functions. Functions are denoted on CTBUH "Tallest Building" lists in descending order, e.g., "hotel/office" indicates hotel function above office function.

office
Structural Material

Steel
Both the main vertical/lateral structural elements and the floor spanning systems are constructed from steel. Note that a building of steel construction with a floor system of concrete planks or concrete slab on top of steel beams is still considered a “steel” structure as the concrete elements are not acting as the primary structure.

Reinforced Concrete
Both the main vertical/lateral structural elements and the floor spanning systems are constructed from concrete which has been cast in place and utilizes steel reinforcement bars.

Precast Concrete
Both the main vertical/lateral structural elements and the floor spanning system are constructed from steel reinforced concrete which has been precast as individual components and assembled together on-site.

Mixed-Structure
Utilizes distinct systems (e.g. steel, concrete, timber), one on top of the other. For example, a steel/concrete indicates a steel structural system located on top of a concrete structural system, with the opposite true of concrete/steel.

Composite
A combination of materials (e.g. steel, concrete, timber) are used together in the main structural elements. Examples include buildings which utilize: steel columns with a floor system of reinforced concrete beams; a steel frame system with a concrete core; concrete-encased steel columns; concrete-filled steel tubes; etc. Where known, the CTBUH database breaks out the materials used in a composite building’s core, columns, and floor spanning separately.

steel
Official Website
Architectural

Height is measured from the level of the lowest, significant, open-air, pedestrian entrance to the architectural top of the building, including spires, but not including antennae, signage, flag poles or other functional-technical equipment. This measurement is the most widely utilized and is employed to define the Council on Tall Buildings and Urban Habitat (CTBUH) rankings of the "World's Tallest Buildings."

349.9 m / 1148 ft
To Tip

Height is measured from the level of the lowest, significant, open-air, pedestrian entrance to the highest point of the building, irrespective of material or function of the highest element (i.e., including antennae, flagpoles, signage and other functional-technical equipment).

362.5 m / 1189.3 ft
Floors Above Ground

The number of floors above ground should include the ground floor level and be the number of main floors above ground, including any significant mezzanine floors and major mechanical plant floors. Mechanical mezzanines should not be included if they have a significantly smaller floor area than the major floors below. Similarly, mechanical penthouses or plant rooms protruding above the general roof area should not be counted. Note: CTBUH floor counts may differ from published accounts, as it is common in some regions of the world for certain floor levels not to be included (e.g., the level 4, 14, 24, etc. in Hong Kong).

84
Floors Below Ground

The number of floors below ground should include all major floors located below the ground floor level.

5
# of Parking Spaces

Number of Parking Spaces refers to the total number of car parking spaces contained within a particular building.

679
Construction Schedule
2021

Construction Start

2023

Completed

Architect
Design

Usually involved in the front end design, with a "typical" condition being that of a leadership role through either Schematic Design or Design Development, and then a monitoring role through the CD and CA phases.

Other Consultant

Other Consultant refers to other organizations which provided significant consultation services for a building project (e.g. wind consultants, environmental consultants, fire and life safety consultants, etc).

Property Management
JLL
Material Supplier

Material Supplier refers to organizations which supplied significant systems/materials for a building project (e.g. elevator suppliers, facade suppliers, etc).

Elevator
Owner/Developer
601 W Companies
Architect
Design

Usually involved in the front end design, with a "typical" condition being that of a leadership role through either Schematic Design or Design Development, and then a monitoring role through the CD and CA phases.

Other Consultant

Other Consultant refers to other organizations which provided significant consultation services for a building project (e.g. wind consultants, environmental consultants, fire and life safety consultants, etc).

Interiors
The Hettema Group
Landscape
HGA
Observatory
Legends
Property Management
JLL; Telos Group
Traffic
Kimley Horn
Material Supplier

Material Supplier refers to organizations which supplied significant systems/materials for a building project (e.g. elevator suppliers, facade suppliers, etc).

Elevator

Global News

21 January 2021 | Chicago

Iconic Chicago Building Getting Massive Plaza Renovation

The owner of one of Chicago’s biggest office towers is investing US$6.5 million to demolish and redesign its half-acre (0.2-hectare) plaza in anticipation of greater...

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.

21 January 2021 | Chicago

The owner of one of Chicago’s biggest office towers is investing US$6.5 million to demolish and redesign its half-acre (0.2-hectare) plaza in anticipation of greater...

23 June 2020 | Chicago

The Aon Center has paused plans to build an observatory with a thrill ride atop Chicago’s third-tallest skyscraper, and the US$185 million project will start...