By 2005, after 120 years of steady growth, Columbia University had filled out every block of its McKim, Mead & White (MM&W)-designed master plan except one—a rectangular allotment on the campus’ northwest corner at the intersection of Broadway and 120th Street. Many proposals had been proffered for the site over the years (including one by James Stirling) but nothing had panned out.

In 1972, construction on the lot was complicated when the university built a bunker-like subterranean recreation center there after student riots in 1968 halted a proposal for a supposedly segregationist gymnasium in nearby Morningside Park. After that point, any structure to rise at the northwest corner would have to bridge the recreation center’s 120-foot clear span—an engineering feat that carried with it an exorbitant price tag.

The mid 2000s, however, found the institution with free-flowing funds and visions of expansion. While drafting schemes for a new campus in Manhattanville, Columbia hired the celebrated Spanish architect José Rafael Moneo to design a building that would not only complete its century-old plan, but also function as a gateway between its native turf and the new lands to the north. Davis Brody Bond Aedas was brought on as executive architect, and Arup was selected as both mechanical and structural engineer.

The north end of the campus is Columbia’s sciences corridor. The MM&W masterplan leaves 20-foot gaps between each building, but all of the science edifices are connected via upper-floor bridges. The one break in this chain is at the northwest corner, between Pupin Hall (physics) and Chandler Hall (chemistry and engineering). The new structure, known simply as the Northwest Corner Building, was slated to complete the circuit and programmed as an interdisciplinary facility with cutting-edge laboratories for physics, chemistry, biology, and engineering.

The convergence of these structural and programmatic demands created a challenge for the design team: To bridge the recreation center, the structure had to be lightweight—using steel was the obvious choice. But to create a stable lab environment the structure also had to be rigid and not prone to the sway associated with most steel structures.

The solution was to design the building as one big truss up and down its elevation by inserting diagonals in the otherwise standard moment frame. This perimeter system stabilizes the structure against vibration, and works in tandem with three heavy-duty trusses running the length of the building to span the recreation center’s roof. The entire assembly ties into eight beefed-up steel columns, three on the south side and five on the north, that transfer the gravity load to a concrete foundation sitting on bedrock.

Unlike Bernard Tschumi’s Alfred J. Lerner Hall, which is partially brick in reference to the campus’ Beaux-Arts vocabulary, Moneo’s building is utterly modern in expression. The street facades, which enclose the lab spaces, articulate the structure. Clear anodized aluminum panels clad the bays with diagonal structural elements, conveying these lines with extruded aluminum fins. While these panels are opaque, the clear bays are outfitted with fenestration. The building’s plaza facade, however, which encloses office space, is an all-glass curtain wall.

Moneo’s building makes some interesting departures from Columbia’s traditional structures in layout as well. In MM&W’s plan, the 65-foot-wide plot would be arranged with a 10-foot-wide corridor running down the middle, leaving 27-foot bays on either side. This is great for classical symmetry, but Columbia wanted to create modern lab space flexible enough to work for any discipline. In answer, the design team skewed the plan, moving the corridor to the east to open up 40-foot clear span spaces for the labs, and leaving narrower bays for the offices. The lab floors are also framed with five-foot-deep castellated beams to allow 18-foot floor-to-ceiling heights, a generous allowance that made room for mezzanine levels for the offices.

The seven lab floors begin five flights above street level, but only a 60-by-60-foot square of the facility reaches Broadway, where there is a lobby. Above the lobby is a café with the same dimensions, and from there escalators lead the student body up to a library, which occupies the building’s full footprint atop the recreation center’s roof. The library is clad entirely in glass on both east and west faces, providing views clear from the campus’ plaza through the building. It is also column free, thanks to the fact that the level above, which holds book stacks and a lecture hall, is home to the structure’s three workhorse trusses, the middle of which shoulders half of the entire load from the floors above.

These trusses were too big and heavy to be shop fabricated and trucked in, and the roof of the recreation center was too weak to act as a staging area; and so the construction team, led by Turner, welded the trusses together on a platform erected above the sidewalk and then slid them into place. Very neatly.