An outdoor transformation

The 17-acre Millennium Park master plan guided the transformation of a once-blighted site in the heart of downtown Chicago into an expansive green roof for the entire city to enjoy. The park opened to the public in 2004, marking the completion of Daniel Burnham’s 100-year vision for the site.

SOM designed the master plan for the park, referencing Beaux Arts-style public spaces through its central promenade, great lawn, and monumental limestone peristyle. At the same time, many of Millennium Park’s features — Frank Gehry’s stainless-steel bandshell, Jaume Plensa’s interactive video installation and fountain, and Anish Kapoor’s captivating Cloud Gate sculpture — imbue the park with a decidedly contemporary feel.

The comprehensive plan also addressed pragmatic concerns and the challenges of constructing a park above a warren of bus lanes, parking garages, and a rail yard. Below the great lawn, two new levels of parking were built, bus stops were added, and rail stations were renovated and expanded. These three systems of transit converge in an efficient, multi-modal center that has reduced and streamlined traffic congestion.

Underground enhancements

Randolph Street Terminal, the commuter rail terminal located underneath the site of the new park since the 19th century, was once hemmed in by rail lines below ground and the street grid above. SOM utilized design, engineering, and lighting expertise to transform an uninviting space into a spacious and inspiring one.

To deal with low and uneven ceilings, SOM conceived a system of undulating, illuminated panels made of perforated stainless steel with a satin finish. The floor, made of blue and white terrazzo, is inlaid with graceful white lines that subtly direct passengers to train platforms.

Further improvements include new glassy storefronts and ticket booths with bands of LED above and below the counters. By integrating light, color, and high-quality finishes into the once-dilapidated station, SOM converted the aging rail terminal into a vibrant and efficient space. Upon completion it was renamed Millennium Station.

Sculpting a memorable pathway

The sinuous BP Pedestrian Bridge is a prominent feature in downtown Chicago, connecting Daley Bicentennial Plaza with Millennium Park. Snaking across Columbus Drive, the 935-foot-long bridge is one of several notable collaborations between SOM and Frank Gehry. In each of these projects, SOM engineers have played a critical role in developing structural systems that support the architect’s sculptural metal surfaces.

At both entrances, curving ramps made of reinforced concrete gently slope upward at a wheelchair-accessible angle of five degrees. Girders connected to underground parking garages help support this part of the bridge. To support the steel walkway as it passes over Columbus Drive, the SOM team created a central pylon anchored to the roadway’s median. SOM engineers succeeded in minimizing costs and materials while preserving the integrity of Gehry’s inventive design.