IF THE TRADITIONAL AMERICAN COLLEGE campus is a cloistered place that draws a clear line between town and gown, then Columbia University’s burgeoning campus in Manhattanville is decidedly untraditional. To obtain regulatory approvals to develop this 17-acre parcel in West Harlem, the Ivy League school agreed to a package of community benefits that includes a local K–8 school and resident access to university facilities. Columbia’s embrace of the neighborhood informed the master plan for the campus, in turn. The 6.8-million-square-foot scheme by Renzo Piano Building Workshop and SOM lacks gates and road closures, and it dedicates all buildings’ ground-floor spaces to retail, health clinics, and other public uses—no keycards required.
In the two years after Columbia dedicated the Manhattanville property in fall 2016, the university constructed three buildings and an outdoor plaza in quick succession. The newly opened Henry R. Kravis Hall is part of the campus’s most recent growth spurt. Designed by Diller Scofidio + Renfro (DS+R) in collaboration with FXCollaborative, the 11-story structure further embodies Columbia’s commitment to community integration, thanks to a scintillating facade that reveals the comings and goings of students and faculty.
Kravis Hall is one of two buildings that make up the new home of Columbia Business School. It faces the eight-story David Geffen Hall, also designed by DS+R and FXCollaborative, across a one-acre park designed by James Corner Field Operations. The pair of buildings comprises 492,000 square feet in total.
According to DS+R associate principal Miles Nelligan, Kravis Hall’s facade is the outgrowth of Columbia Business School’s desire to buck another tradition of higher-education buildings, namely the separation of faculty offices and student spaces. Inspired in part by guaranteed public access to the ground floor, Nelligan recalls that the design process “started with some very passionate conversations about breaking down spatial and population hierar- chies; we were encouraged early on to integrate all the school’s populations into one project.”
To ensure that students and professors would commingle outside of the classroom, the design team organized Kravis Hall into alternating floors
for learning and faculty use. Arup, which consulted on the project’s structural engineering, envelope, and facade, devised a so-called skip-truss system
to support that configuration. The overall building structure comprises ASTM A992 Grade 50 beams fastened to steel columns on composite floors, with webs placed throughout the grillage for additional bracing; the webs greatly increase in frequency on faculty floors to support the classrooms and other wide-open spaces on student floors.
“There was an architectural interest and a client interest in shuffling the buildings into layers. We thought it would be interesting to do the same with the structure,” says Arup principal Dan Brodkin, who adds that modular, highly partitioned faculty offices lent themselves to nesting within the more robust structure. Columns are typically W34 sections; beams range from W12s to W30s; and W10s, W12s, and W14s make up the webs. The system ties into the steel of an underground structure that had been commissioned separately.
Recognizing that professors or students could sequester themselves even in a layer-cake scheme, DS+R and FXCollaborative also pierced the building with two visually distinctive staircases whose landings are surrounded by multipurpose spaces. “This was a reaction to how and where education takes place in academic buildings, which is not only in the classrooms.
It’s about interactions, the time outside class, the group work, the socialization,” Nelligan says of transforming conventional circulation into a verti- cal quadrangle. The routes inserted along Kravis Hall’s west and east elevations are respectively earmarked for faculty and student movement. Because students tend to linger on campus despite not having a domain to officially call their own, landings that radiate from the student stair are especially commodious.
Both the alternating floors and unifying stairs are legible to passersby. Faculty floors are wrapped in a curtain wall whose vision glass includes a white ceramic frit on the exterior, which lends the surface a milky quality while modulating incoming daylight for the perimeter faculty offices. Student floors are finished in transparent glass planes that are inset from the floor plate’s edge. The two stairs employ the same code, moreover: the faculty stair is expressed on the west elevation as a fritted-glass plane that zigzags among the horizontal wedges, and clear inset glass wends up the east elevation to reveal the student stair. As Nelligan puts it, “The building is very honest about what’s going on inside.”
That the facade steps in and out alongside the alternating floors confirmed the need for Arup’s skip-truss structure, says Jeroen Potjer, a senior structural engineer at the firm: “We couldn’t place columns directly at the perimeter, because of the layered composition. The skip system is always perpendicular to the face, to accommodate those long cantilever conditions of approximately 12 feet.” Arup also conceived a “ladder-truss system” to support those areas of glass that span multiple stories. In these places, two parallel ASTM A500 rectangular HSS are set in from the facade, and the tubes link via horizontal elements.
The project team then engaged W&W Glass in design-assist to create Kravis Hall’s communicative skin. “Design assist helps us with constructability and installability,” W&W project manager Ryan Malynn says of the delivery method, which inserts manufacturer feedback early in the design process. Malynn adds, “Because this building has a lot of unique setbacks and deep soffits, we were more in control of how our steel connected to the structure.”
After performing its own load analysis, W&W worked with Arup to introduce kicker angles and other stiffening techniques, so that Kravis Hall’s structure could support the company’s preferred configurations and connections. In parallel, W&W determined to execute the faculty facades as unitized curtain walls. Meanwhile, the transparent glass of student floors are stick-built window walls that have their own structural steel support system at the head and concrete curbs at the sill. “Because of the way every other floor steps back, every single floor has its own starter track,” Malynn also notes of the alternating systems. (Storefront glass wraps the ground floor.) All standard systems absorb thermal, seismic, and differential movements of approximately 1 inch, according to Malynn’s fellow project manager Matthew Keefe.
The stick-built walls are hanging systems, in which the steel head dead-loads the panels. Keefe points out that W&W also had to take into consideration large live load and drift movements, given that the three east-facing walls abutting the student stair span two or three stories. The company responded by adding aluminum-clad, ASTM A500 50 KSI rectangular HSS mullions to the glass, setting them into the starter tracks with base anchors. The mullions were set in section and spliced in the field.
“It was quite a road to travel, to create a system that can adapt to all these bespoke situations,” Nelligan says of W&W’s efforts. Of making build- ing activity and the urban context visible to one another overall, the architect adds, “at Columbia Business School, you know you’re in New York.”