Rob Chmielowski
Senior Principal
Magnusson Klemencic Associates, Seattle

Towering over Chicago’s West Loop riverfront, the 54-story 150 North Riverside office building is a striking example of engineering innovation. Completely transforming a 100-year-old, vacant lot into a thriving work space that includes a vibrant 1.5-acre public park, the project redefines structural engineering ingenuity with a slender design driven by necessity, not aesthetics.

Constructed on a site previously deemed “unbuildable,” 150 North Riverside features a razor-thin structural core to accommodate its postage-stamp sized lot, measuring just 85 feet (25.9 meters) at its widest. Wedged between the Chicago River’s south branch to the east and seven active Amtrak lines to the west, the narrow site, along with a 30-foot setback at the river for Chicago’s Riverwalk, left only a 39-foot (11.8-meter) sliver for a high-rise tower. To resolve this challenge, Magnusson Klemencic Associates (MKA) designed the concrete core to be three times skinnier than a typical office building, which reduced the building’s base footprint by 80 percent and strategically avoided the seven active train tracks below.

Rob Chmielowski discusses how MKA collaborated with architect Goettsch Partners and contractor Clark Construction, to achieve the project’s many engineering accomplishments that ultimately led to 150 North Riverside’s impressive success. These include the first-use of a tuned liquid sloshing damper to control building drifts; the design of 16 sloping columns featuring the largest rolled steel sections in the world; the United States’ first use of high-strength 70 ksi steel; and the highest capacity micropiles ever used in the City of Chicago.