The square shaft form - a departure from traditional slender shaft/bulb-top towers - evolved in response to two challenges: Chicago’s classification of the tower as a high-rise, requiring dual stairs (previous towers had one); and FAA’s need for direct/minimal pathways/distances in routing cabling/electrical/mechanical from the Junction Level into the Cab above.
The solution inverts conventional solid-core tower plans, pushing “core” elements to the perimeter, thereby opening the center for feeds directly up to the cab. The shaft provided an economical, non-combustible structure utilizing standard formwork for fast construction. The concrete edge is expressed as a “ribbon” framing glass-clad stairs and visually ties the Tower, Base Building and Ground Plane.
The Base Building is organized in parallel bars - one housing MEP to the north to buffer taxiways; the "people" bar, located to the south to maximize daylight/views, and present a friendly face to employees and visitors.
There are no extraneous elements - everything is integrated. The result is a simple, 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 an iterative process with architects, engineers and controllers focused on providing flexibility and adaptability to integrate new systems as technology advances. The FAA considers this tower a significant advancement that now serves as the new precedent for the design of future towers.
The South Tower is the first at O’Hare to achieve a 4-Airplane SAM Rating (Sustainable
Airport Manual - an Aviation-specific sustainability metric) and will be only the
third in the U.S. to achieve LEED Gold. The design was driven by a pursuit of effective
sustainable strategies from design through construction that ranged from simple yet
important form decisions related to minimizing overall building volume; to the inclusion
of sustainable energy and efficiency (geothermal); to the selection of sustainable
materials for both structure and finishes; to ease and speed of construction processes
(simple concrete structure and jump forming construction methods, etc.).
Control of the Tower Cab environment is critical for the operations, therefore a dedicated
constant volume AHU with 100% standby capacity serves the Cab area. Glass
sensors maintain correct dew point to avoid condensation or fogging on Cab glass.
• Energy modeling was used to estimate total energy consumption with the goal of
exceeding the LEED requirement of 10% below ASHRAE Standard 90.1-2007. Reports
indicate a 14% reduction in energy usage compared to baseline;
• A groundwater source geothermal system was used to enhance the energy efficiency
of heating and cooling systems;
• No CFC-based or HCFC-based refrigerants were used;
• A Measurement and Verification Plan was developed by the CxA to monitor energy
consumption for at least one year after occupancy;
• The design exceeds requirements of ASHRAE 62.1-2007 for ventilation.
• CDA purchased renewable energy certified by Green-e;
• Air handling units were provided with filters that have a Minimum Efficiency Reporting
Value (MERV) rating of 13 or higher and separate carbon filters.
Energy performance rating: Design: 85 Target: 75
CO2 Emissions: Design: 422 mt/y Target:474 mt/y
CO2 emissions reduction: Design: 28% Target: 19%
Energy cost savings: 14.22%
Being located in a remote airfield, the Tower is not technically a public building. It is accessible
via public transportation via CTA and connection to airport shuttles. The design
provides designated parking for car/vanpool and low-emitting vehicles and includes
showers and bicycle racks for alternative transportation
40% water use reduction
• No irrigation - native low-maintenance vegetation (doesn’t attract wildlife that
would be threatening to aviation operations)
• Stormwater storage under parking
• Low-flow plumbing fixtures fittings
• user recycling program
• 95% construction waste recycling
• construction materials recyclable
• 30% regional materials