Two Illinois Center

The Two Illinois Center is an International Style skyscraper designed by Mies van der Rohe, with Fujikawa Conterato Lohan Associates as lead architect, and built between 1970 and 1972 in Chicago, IL.

Its precise street address is 233 N. Michigan Av, Chicago, IL. You can also find it on the map here.

Together with One Illinois Center, Two Illinois Center comprises the Illinois Center, which is primarily dedicated to office space.

The streets that intersect the complex are structured on three levels: the middle level facilitates direct traffic, the lower level is designated for service vehicles, and the upper level handles local traffic.

Within the building’s underground pedestrian walkway, a vibrant community of commercial services caters to the general public. This area is connected to three levels of underground parking that are shared across the entire complex, which also includes four hotels and provides access to both the El and Metra train lines.

The building underwent a major restoration in 2018. The architect commissioned to undertake this restoration was Goettsch Partners.

Mies van der Rohe, with Fujikawa Conterato Lohan Associates as the lead architect, was the architecture firm in charge of the architectural design.

The Two Illinois Center can be categorized as an International Style building.

The Two Illinois Center uses a frame structure made of columns and reinforced concrete slabs.

A frame structure uses a combination of beams and columns to sustain the building's weight. The walls in this case are non-load bearing, which allows for more flexibility when distributing the interior spaces.

The facade uses a non-load bearing curtain wall system. This means the curtain wall modules are anchored to the building's structural frame, typically by being attached to the edge of the floor slabs. The curtain wall system connects to the slabs using brackets, anchors, and mullions, which transfer the loads imposed by wind and temperature changes, to the building's primary structural elements.

This setup allows the curtain wall to accommodate differential movement between the facade and the structural frame, such as thermal expansion, floor deflection, or sway from wind forces. This system's integration with the slab edges also allows for continuous insulation and weatherproofing layers.

From an aesthetic point of view, the facade features a curtain wall made of bronze-colored anodized aluminum and polarized glass windows.

At the base the facade takes a step back, leaving the columns exposed and creating an open public gallery, as it is usually the case in Mies's buildings.