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Neighborhood Stacks

Zinc-wrapped, vertically stacked building offers panoramic views of Chicago

Rubenstein Bldg Profile May21 1

Photo: Brett Beyer

Located prominently on Chicago’s Midway Plaisance public park, across from The University of Chicago’s Rockefeller Memorial Chapel, the new David M. Rubenstein Forum at the University of Chicago offers expansive views of downtown Chicago and Lake Michigan, as well as the University campus and Woodlawn community.

Opened on September 28, 2020 and designed by Diller Scofidio + Renfro (DS+R), New York City, The Forum is a space of discourse and intellectual exchange aimed at fostering the outward engagement of visiting scholars, researchers and dignitaries from around the world. Sean Gallagher, project director for the Rubenstein Forum, and DS+R director of sustainable design, says a central vision was to create a “Progressive Retreat” that would expand on the university’s foundation as a scholarly retreat within the city of Chicago, or a “retreat within a retreat.”

“We needed to make a complex that could promote both focused and spontaneous encounters,” explains Charles Renfro, partner, DS+R and partner-in-charge for the Rubenstein Forum. “The goal was to negotiate between those two conditions: one part of the building that is more focused on presentations or discussions where the city fades away, and another part of the building that allows for casual encounters, free conversation and an engagement with the city. The design was a balancing act between the extrovert and introvert qualities that the project required.”

Photo: Brett Beyer

Staggered Towers

The 97,000-square-foot building is composed of a two-story base and a slender, eight-story tower, and provides the school with a 285-seat auditorium and much-needed multipurpose meeting spaces for workshops, symposia and lectures, among other activities. The tower is organized as a stack of neighborhoods with meeting and communal spaces that offer diverse environments from formal and informal, calm and animated, focused and diffused, and scheduled and spontaneous. Each of the neighborhoods merge around a central private social lounge that offers a sense of community and identity. Vertically stacked, the neighborhoods are rotated and oriented to their own unique perspective of Chicago, creating a panoramic 360-degree form.

By drawing on Chicago’s rich history as the birth of the skyscraper, the architects proposed a unique tower that would sit in direct conversation with the surrounding campus’ architecture. “We were really interested in using the verticality of the tower to stitch the south side of Chicago together with the north side and the north campus, equally addressing both sides of the city,” Renfro explains. “We also wanted the building to express a spirit of openness, connectivity and engagement with the surrounding community. The program opportunity we seized on and emphasized was to allow the communal spaces to contribute to the image of the building, and to group them together to produce a bigger impact. The neighborhoods are formed by alternating double-height social spaces and meeting spaces, and because the social spaces are smaller than the meeting spaces by definition, these cantilevers started to emerge. This staggered structure prompts the building’s varied populations to cross paths with one another, where possible, to enhance intellectual exchange.”

Photo: Brett Beyer

Zinc-Wrapped Façade

The building’s curtainwall system was designed and engineered to provide unobstructed views toward the campus and the city. To minimize transitions between interior finishes and the façade, the curtainwall is base supported at all locations, and consists of steel-reinforced, unitized aluminum panels and high-performance insulating glass units with low-E coatings and bird collision avoidance measures.

Gallagher notes that the choice of zinc and aluminum composite panels (ACM) were related to the overall building concept. “The alternating north and south zinc chamfers below each neighborhood guides visitors into a shared double story social space that offers sweeping views of Chicago. A double-story glass curtainwall encloses the ends of these chamfered walls providing weather protection and allowing visitors to feel as if they are outdoors enjoying the view.”

Additionally, the ACM edge chamfers absorb the movement between the glass curtainwall and concrete cantilevers to create a more resilient building envelope. “These ACM chamfers became a unique feature of the design that frames the picture window to Chicago,” he says.

“Zinc as a material ages naturally and reflects light in subtle ways that will improve over time. The shiplap zinc panels on the east and west walls stitch together the meeting room neighborhoods and create a building composition that is much more fluid and vertical than stacked boxes,” adds Gallagher.

Photo: Brett Beyer

Engineering Details

Tuschall Engineering Co. Inc., Burr Ridge, Ill., acted as the design-assist partner for the metal cladding system, and provided a variety of different colors of zinc, embossing patterns, panel types, interfacing with the ACM panels, soffits, roofs, interior panels, attachment system to concrete, thermal break backup structure and insulation.

James C. Tuschall Sr., president of Tuschall Engineering, notes that extensive detailed mockups were built to confirm design intent along with any constructability issues to work out. The building structure the panels were attached to was primarily a series of cast-in-place concrete boxes. The panel system depth varied from 4 1/2 inches to 1-foot, 2 inches and in some areas was not parallel to the face of the concrete. “This required several different depths of extruded aluminum thermally broken clips, vertical aluminum rails and horizontal aluminum channels,” says Tuschall.

ATAS International Inc., Allentown, Pa., custom fabricated 60,000 square feet of flat lock and Shiplock panels with 1-mm Gray Zinc supplied by Tuschall Engineering. DAMS Inc., Alsip, Ill., fabricated 7,000 square feet of 4-mm Reynobond ACM FR rainscreen in a Natural Brush finish from Arconic Architectural Products LLC, Eastman, Ga. Tuschall Engineering installed all of the metal wall panels, in addition to the Nvelope support system supplied by SFS Intec, Wyomissing, Pa.

“The panels all line up with the center axis point and at each condition all panel joints are aligned vertically,” explains Tuschall. “Additionally, the wall joints transition to the roof and soffit joints creating continuous alignment from the east-to-west elevations. This took careful planning and execution to achieve.”

Blackened steel was used as an accent material on almost every floor. “On the ground floor guests are welcomed by a lobby featuring a continuous surface made of 1-inch blackened structural steel that winds through the space, functioning as a cantilevered reception desk, as well as the guardrails for the lobby grand stair and bridge,” Renfro explains.

“The buildings we make are not strictly formal in nature,” says Renfro. “Our goal is always to design projects that create relationships with their site and surrounding community. While the Rubenstein Forum is fun to look at from the outside, what's really special about the building is when you go up and look out from the windows and see the campus and the city presented to you. It's dramatic and beautiful and the building fades away. You stop looking at the particularities of the architecture, and the building becomes an instrument for experiencing what the architecture yields.”