THE VIEWS FROM HIGH FLOORS at One Vanderbilt, the 77-story Kohn Pedersen Fox tower that opened last September, can induce a moment of awe in even the most jaded New Yorker. Viewing the spires of the Chrysler and Empire State Buildings from above was once a perspective afforded only from aircraft. At 1,401 feet, One Vanderbilt is the tallest office tower in Midtown and the fourth tallest building in the city.
Any supertall skyscraper is, among other things, an embodiment of optimism. Who, after the past two years, has had much room for optimism? Employment rates and commercial rental markets have taken a hit. The ad hoc shift to work-from-home has reduced demand for office space either momentarily or permanently, as workers and organizations reassess which activities do and don’t need physical presence. There will inevitably be observers who believe a major new Class
A commercial building is the last thing the city needs, and not all of them are NIMBYs.
The team that gave the city One Vanderbilt, however, is looking beyond the present and near future. The new building, they contend, is more than just a paragon of sustainability, with $17 million worth of investment in features that give it an exceptionally low carbon footprint for its scale. It emerges from a pathbreaking public-private partnership involving the City of New York and the Metropolitan Transportation Authority (MTA). And it is essential to the reinvention of East Midtown, the 78-block area that City Council rezoned in 2017 with an eye toward relieving congestion, encouraging transit use, and upgrading aging building stock. Occupying the block bordered by 42nd and 43rd Streets and Madison Avenue, and replacing the lowest block of Vanderbilt Avenue with car-free space adjacent to Grand Central Terminal, the building may be the nation’s most conspicuous example of transit-oriented development.
The neighborhood’s need for up-to-date and uncrowded space is clear. One Vanderbilt not only contributes 1.7 million square feet of commercial space but integrates on multiple levels with the terminal. “The One Vanderbilt project included $220 million in public transit improvements,” Moss says; these include a new subway entrance, a 4,000-square-foot transit hall inside the tower, and ADA elevator access to the subways and trains. “The improvements will allow for one more train to run on the congested 4/5/6 subway line per hour, which will help relieve congestion during peak hours.”
One of the building’s distinctive qualities is its deference to other elements of its neighbor- hood. “A major challenge was to design a super-tall structure
that would not overshadow, but complement, its neighbor Grand Central Terminal,” Severud’s Daniel Surrett says. By convert- ing a block of Vanderbilt Avenue to a 14,000-square-foot plaza, redistributing space from motor vehicles to pedestrians and trees, One Vanderbilt increases safety while giving people more room to move and breathe. Its facade rises two stories west to east along its south face to expand views of Grand Central beneath its signature oblique cantilever and orange soffit. Jules-Félix Coutan’s sculpture Glory of Commerce (1914), showing Mercury, Minerva, and Hercules surrounding Grand Central’s exterior clock, is no longer obstructed from the west by a Modell’s Sporting Goods.
With tapering trapezoids, One Vanderbilt loosely resembles an update of the diagrams that Hugh Ferriss drew to illustrate the principles of New York’s 1916 zoning law, the regulation that established setbacks admitting light to the streets throughout Manhattan’s business districts. Ferriss’s sharp pyramidal forms were a transitional condition, an abstraction to which orthogonal wedding-cake setbacks aspired. One Vanderbilt dares to literalize such geometries, suggesting a tall ziggurat or, in the uppermost segments, a craggy iceberg. These nonorthogonal volumes and oblique load patterns called for careful handling by the structural engineers, whose close involvement with the designers from early stages resulted in time- saving, problem-solving measures on multiple fronts.
“Three faces of the building step outward at the fourth floor, including the southern face,” notes Moss. “Cantilevered trusses are provided to pick up columns at the fifth floor, while the outer regions of the fourth floor are hung from the top chord of the cantilever. As you move toward the east of the building’s southern face, the transfer trusses become shallower, allowing the structure to fit within the angled facade profile. The uplift forces in the back spans of the cantilever trusses are resolved by connections to the core shear walls.”
The prominent notch in the east facade is achieved by sup- porting perimeter columns on cantilevered steel trusses and plate girders that are tied back to a robust concrete core. Truss members are custom-fabricated out of ASTM A572 Grade 50 plates up to 8 inches thick and welded together, since the load demands exceed the capacity of standard rolled shapes. The plate girders are fabricated out of the same material and sizes. Connections
at truss panel point nodes were built up out of laminated plates seam-welded together. In some instances, forces at nodes were so great that isotropic solid steel forgings with the greatest dimension exceeding 8 feet were necessary to transfer them.
Many of Midtown’s older commercial buildings have 20×20-foot column grids, considered obsolete by tenants who prefer open floor plans. In One Vanderbilt, Surrett says, “there are no perfectly vertical steel columns in the building below the highest occupied floor, and an effort was made to keep the corners of the structure column-free.” End connections of beams were designed to resist the lateral ‘kick’ forces induced by the slopes of the columns. The outrigger trusses on dedicated mechanical floors tie the perimeter columns to the core to engage them in the lateral sys- tem and effectively create a wider base to resist lateral shears and overturning moments. Outrigger trusses were skewed slightly along the four sides to hit shear wall intersections and provide the most direct load path possible. Column-free beam spans approach a maximum of 70 feet. Vibration of the floor systems was considered extensively, and in many instances controlled the de- sign of floor beams over strength or deflection.
Severud’s Edward M. DePaola points out several benefits of the non-orthogonal design. “The slope of the façade is always on the main axes of the building (either north-south or east-west), so floor spans remain consistent on every floor. The taper results in less width of building surface (sail area) with height.” Because wind pressures are larger on higher floors, these reduced floor areas result in less wind-shear force on the building. Midtown’s density can contribute to complex wind patterns as prevailing southwest winds move around other build- ings; the design/construction team conducted wind-tunnel testing, using “a ‘proximity model’ that takes into account the sur- rounding neighborhood, the low and tall buildings, the avenues and the streets, so everything that may affect wind loads on the building [is] taken into account…. Together with the architect, we were able to ‘notch’ the corners of the tower. That shape helps break up the eddy currents that form downwind as the air mass travels past the building. The spire used the same concept,” says DePaola.
Vibration from below posed a potential challenge for a building married to a major transit node, but “the mass of the cast-in-place concrete foundation walls and concrete core provide vibration and sound mitigation such that isolation pads in the foundations are not required,” Surrett notes. DePaola points out that the only line adjacent to the property is the 42nd Street Shuttle between Grand Central and Times Square; vibration analysis indicated that the low-speed S trains, which stop west of Madison Avenue, have no impact on One Vanderbilt. Metro North tracks are also far enough away to have no effect. Another stabilizing element is a 520-ton tuned mass damper at the top of the building, which moves out of phase with building deflections to reduce wind-induced accelerations and increase comfort for occupants. “It is tuned to match, as closely as possible, the building frequency and period,” DePaola says; its tuning makes it effective during one-year and ten-year storms. The damper’s effect is sufficient, Surrett observes, that “space at the top of the building, with amazing views, may support uses as sensitive as fine dining.”
KPF architect Andrew Cleary, speaking at an American Institute of Steel Construction panel in September 2019 shortly after One Vanderbilt topped out, noted that after breaking ground in October 2016, the project progressed ahead of schedule and under budget. Real-time parametric analysis accounted for much of this performance: using Rhino, Revit, Grasshopper, the model- ing program Tekla, and Thornton Tomasetti’s proprietary collaborative BIM system Konstru, the design process determined pre- cise details such as exact beam lengths, bolts, and welds earlier than on conventional design- bid-build projects. Modeling allowed early coordination of all subcontractors and prevented onsite clashes. “If we catch one hitch that typically would happen during construction, we’ve paid for these guys to come in early,” Cleary noted; “if we catch two, we’re ahead of the game.”
One Vanderbilt is a structural hybrid with a steel frame and concrete shear walls. In a departure from routine practice, the light steel frame was erected first along with the main framing; the concrete core followed, about 10 floors below the steel, with the pouring of the floors. Moss describes “a lateral system that allowed for steel construction to be up to 12 floors ahead of core shear-wall construction. The steel members were designed to fit within the shear walls. We added shear studs to the steel members, allowing the shear walls to engage the embedded steel structure. This construction sequence required additional steel tonnage, but it allowed for a faster construction cycle.” DePaola credits firm founder Fred N. Severud with the steel-first erection sequence—“the Severud system, I like to call it,” keeping different trades from holding up each other’s progress.
Planning the steel and concrete operations required detailed advance measures. “Mechanical couplers for rebar splices were utilized in lieu of lap splices extensively to reduce congestion between the steel frame and the rebar and minimize” the thick- nesses of the shear walls,” Surrett says. “Strategically placed copes and holes were provided in steel beams and connection plates to allow the continuity of vertical and horizontal reinforcement. Add to that the accommodation of shear wall penetrations for MEP distribution in and out of the core, and you have quite the puzzle to solve. Design concrete compressive strengths were up to 14,000 psi, and lab test results consistently exceeded expectations. One notable accomplishment was pumping over 4,000 cubic yards of concrete into the building’s mat foundation in a continuous pour in sub-freezing temperatures.” The 27-hour operation in February 2017 was one of the largest single pours in the city’s history.
The process, which DePaola likens to “a ballet,” has yielded a building with a well-integrated aesthetic presence as well. The oblique-angle motif of the cantilevered south facade is matched by ventilated spandrel panels at each floor, including 34,845 glazed white terra cotta tiles molded with an identical angled pattern rising left to right; upper unoccupied segments near the spire pick up the same motif, complicating the building’s verticality with a consistent visual rhythm. The facade includes 8,743 curtain-wall panels in 1,060 different configurations, composing 753,500 square feet of curtain wall.
Developer SL Green is a believer, not just an investor: the firm is moving its own headquarters into the build- ing. They and other tenants will enjoy a 30,000-square-foot amenity floor with a 145-person auditorium, lounge, boardroom, and outdoor terrace, among other perks. On the 59th floor, an observation deck designed by Snøhetta, The Summit at One Vanderbilt, includes two glass ledges above Madison Avenue—a view to rival KPF’s other recent vertiginous project, the Edge at 30 Hudson Yards.
The supertall category attracts reflexive skepticism in some quarters, especially in the wake of Hudson Yards, where ten-digit public expenditures aided luxury- level private interests without arguably creating corresponding civic benefits. In the case of One Vanderbilt, however, skeptics will need to consider nuances and recognize the details of the public-private negotiations. Approval did not come easily here. In return, the city gets some badly needed transit upgrades, ample property taxes, the addition of a pivotal location to the local reservoir of vehicle-free space, and a model for the continued greening of future skyscrapers—plus a resounding rebuttal to those who believe New York’s glory days are behind us, that the future has no room for the exhilaration of thousand-foot views.