2011 AL Design Awards: 155 North Wacker Drive, Chicago

Following the tradition of great Chicago high-rise office buildings, 155 North Wacker Drive first roots itself to the street with a grand lobby and atrium before it begins its 46-story climb toward the sky. Its use of bold geometric forms coupled with skilled lighting design create a distinct public–private space.

The transition from street (the public realm) to lobby (the intermediary private realm) is made seamless thanks to the strong form of the diagonal ceiling grid overhead. Bands of light accentuate the diagonal grid courtesy of concealed LED strips located in an architecturally constructed cove. LEDs were selected for their ability to withstand changes in ambient temperature. To further balance the color temperature, recessed double-lamp ceramic metal halide accent fixtures are also concealed in the cove.

To highlight and soften the powerful presence of the elevator core’s exterior stone walls, metal halide accent lights equipped with spread lens assemblies brush the surface with a soft wash of light. A perimeter cove along the lobby’s back stone wall uses indirect fluorescent striplights so that the origami-like folded planes of the diagonal ceiling grid appear to float. All sources are color-matched to 3000K for a balanced effect.

At the elevator core lobby interiors, asymmetric ceramic metal halide floodlights concealed in a carved slot in the core wall create a warm accent and provide another layer of scale to soften the intensity of the core’s volume.

Jury Comments: The designers have taken an idea and detailed it incredibly well. • It’s quite a feat not to see the glass. • It has a medieval design quality.