O’Hare International Airport South Air Traffic Control Tower

Chicago, Illinois / United States of America

The Tower's extruded square shaft form - a departure from traditional slender-shaft bulb-top towers - evolved in response to two primary challenges:  Chicago’s classification of the tower as a high-rise with the requirement for dual fire exit stairs (previous towers had one stair); and secondly, FAA’s need for direct/minimal pathways/distances in routing critical cabling/electrical/mechanical services from Junction Level into the Cab above. 

The solution inverts conventional solid-core tower plans, pushing “core” elements (elevator/stairs/shaft) to the perimeter, thereby opening the center for equipment feeds directly up to the cab. The concrete shaft provided an economical, durable, non-combustible structure that utilized standard formwork for fast construction.  The concrete edge is expressed as a “ribbon” that frames the glass-clad stairs and visually ties the Tower, Base Building and ground.

The Base Building is organized in two parallel bars - the taller houses MEP and is situated to the north as a buffer to active taxiways; the "people" bar, is located to the south to maximize daylight and views, and present a friendly face to visitors.  Exterior mechanical equipment is integrated within the trellised end bay.

There are no extraneous elements - everything is integrated and has a place and purpose. The result is a simple, durable and elegant tower that speaks to the efficiency of the FAA’s operations, the importance of O’Hare as a world-class airport and the reputation of Chicago as a hub of exceptional architecture.

The project began with the directive to site-adapt the FAA's standard control tower prototype.  This alternative design evolved out of a collaborative iterative process with architects, engineers and controllers focused on providing flexibility and adaptability to easily integrate new systems as technology advances. The FAA considers this new tower a significant advancement that now serves as the new precedent for the design of future towers. 

Architect of Record



Federal Aviation Administration + City of Chicago Department of Aviation

General Contractor

Walsh Construction