ROCKEFELLER UNIVERSITY WAS
facing a quandary. As a leader in biomedical research, it sought to significantly expand with new state-of-the-art laboratory facilities, but was essentially out of real estate. Fortunately, the university owned the air rights on FDR Drive’s east side, which allowed it to commission the design of a 900-foot, three-story building, designed by Rafael Viñoly Architects (RVA), that would rise along and over the highway.
The new 180,000-square-foot building, known as the Stavros Niarchos Foundation–David Rockefeller River Campus, spans almost three and a half city blocks and aggressively addresses the vibration and thermal-control needs of the laboratory. But perhaps the most unique challenge was erecting the large, long structure on a site with the East River on one side and a limited staging area on the other.
“We basically had to build a bridge over a hundred-foot stretch of the FDR,” says Jay Bargmann, Vice President and Managing Partner of RVA. “It was our idea to prefabricate the building. It seemed to me very odd that you could build a temporary bridge over the FDR and then stick-build a building over it; you were still jeopardizing traffic and having to transport materials to a difficult site with that method.” Bargmann says the project’s structural engineering team at Thornton Tomasetti jumped on the idea of
prefabricating the building off-site. Construction manager Turner also came on board with a project manager, Curt Zegler, who “really pushed the idea forward once he understood it,” he says.
The building team’s creative solution involved prefabricating 19 steel-framed modules at the off-site staging area—each approximately 92-feet by 48-feet on three-levels, complete with castin-place concrete on two levels, fireproofing, sprinkler systems and conduits—and then transporting them on a barge across the river. Because the modules already weighed close to 800 tons each, ductwork and concrete deck were installed on-site. The prefabricated approach, “was the safest way to build the building and it was the least disruptive to the community and the city as a whole,” says Bargmann. “Reducing construction time also reduced the cost,” says Bargmann. In a traditional construction workflow, materials would have had to come across the George Washington Bridge and across the one point of access from the FDR to Rockefeller’s Campus. But prefabricating the modules off-site shaved approximately 12 months off the project schedule and saved $20 million to bring the total project cost to $500 million. In addition, this approach minimized risk i.e., exposure to passing vehicles during construction—and created a highly integrated environment with RVA, along with Thornton Tomasetti, Turner, construction consultant Lehrer, and steel fabricator Banker Steel, working closely together to fine-tune the design and complex prefabrication, transport, and erection processes.
“Over two and a half months in the summer of 2016, one module was lifted each of 19 nights using a Chesapeake 1000–a rare, 1000ton barge crane,” explains Sherry Yin, an associate principal for Thornton Tomasetti. To optimally stabilize the modules during transport, a temporary support system was installed and anchored to the deck of the barge. “The barge crane was only able to operate during a steady slack tide, and since the lift had to coincide with the FDR closure from 12 a.m. to 5 a.m., there were specific days on which the lifts could take place.”
During each crane hoist, a module was supported by 16 computer-controlled cables that would keep the load completely level, explains Bargmann. “That was tested on the staging site in New Jersey so the computer knew what tension or load had to be carried in each level. They repeated that when they got to the site.” With no overtime or contingency allowed because of the tides and FDR closure window, “You couldn’t be an hour late,” he adds. “It’s a remarkable compliment to the team that did the erection.”
During the day, strict safety measures were employed during construction to ensure the safety of the more than 175,000 vehicles driving down one of Manhattan’s busiest roadways on a given day. Dictated by the vehicle clearance on FDR and the need to match existing campus elevations, twostory Y columns were spaced at 96 feet on center on the building’s east side. They are supported on pile caps with multiple mini piles, in place of large caissons, due to limited capacity for equipment on the esplanade. The columns on the drive’s west side are spaced at 48 feet on center, according to Yin. “The primary superstructure consists of two levels of highstrength plate girders spanning up to 92 feet over the FDR Drive that are linked by diagonals so that both plate girders, each approximately 5 feet deep, act together like a truss,” she explains. “This also supports a green roof on the third level.”
In all, the David Rockefeller River Campus has added two acres, four buildings, expansive laboratory space, landscaping and beautiful East River views to Rockefeller University’s existing 14-acre campus. Two curvilinear glass pavilions—one housing dining facilities and the other for offices—emerge from the gardens that cover two levels of labs below. The structure’s long, slender form is accented by horizontal brise-soleil that shield the glass curtain wall, best viewed by Roosevelt Island’s shoreline on the East River.
The floor-to-ceiling glass provides a great view of the River while carefully calibrated ceiling heights enable daylight to enter deep into the interior where automated roller blinds shield the scientists from glare.
Although the zoning of the University’s land would have permitted a more vertical solution, the architect opted for a stretched-out, horizontal design for optimized research collaboration and flexibility with future laboratory changes and needs. The layout consists of two open floor plans, approximately 740 feet long. They are divided by a lounge space for informal meetings and coffee breaks to encourage interaction amongst researchers.
For specialized equipment requiring enclosed rooms, those are positioned along the wall adjacent to the existing campus with the scientists’ offices reserved for the prime real estate facing the water. Meanwhile, a middle zone with roughly 90-foot-deep floor plates are used for lab benches. Under the raised floor sits the extensive power, data and gas infrastructure required of a 21st century laboratory. The casework and floor system are designed on a 2-foot-by-2-foot grid for a readily reconfigurable, “plug and play” setting.
While the new addition is primarily used as laboratory space, the University has added a health and wellness center and an interactive conference center with a glass facade facing a broad lawn. As noted, minimizing vibration was a major issue for the world-class laboratory. With its long spans, the building was particularly vulnerable as issues like rumbling vehicles along the highway and indoor foot traffic could easily impact sensitive equipment and skew research results.
“The rules of thumb frequently employed for vibration analysis were not going to be adequate,” relates Lin. “We approached the design by performing detailed dynamic analyses of the overall structure and tuned the sizes to satisfy the vibration limits required by the laboratory.”
The long-span structure also presented a thermal movement issue. Addressing this involved ensuring a complete load path for thermal and lateral loads which consists of a 1,000-foot-long diaphragm resisted in the short direction at four middle points. “A comprehensive thermal analysis was performed to ensure no excessive stress induced in structural components,” she explains. “The two shorter Y columns at the northern end are released from diaphragm constraints via application of a spherical sliding pad.”
Thornton Tomasetti also developed a special drag member using plates welded to the top of steel beam/girder to eliminate conflict and minimize the connections.
In addition, the team faced a few challenges in working with the west-side foundation, which was on the rock adjacent to an existing schist wall. Close and extensive collaboration with the Turner and subconsultants on-site solved issues such as higher rock elevation, overlapping with the Schist wall, and circumventing conflict with existing underground utilities and fixtures.
Lending some perspective on the magnitude of this project, Thornton Tomasetti Senior Structural Engineer Thomas
McLane, P.E., says that before the steel could be moved and put into place, the initiative involved years of designing and thousands of shop drawings requiring careful review. “You don’t see too many projects of the same scale with Y columns, cantilever diagrams, and modular construction,” he explains. In terms of the prefabrication, module transportation and on-site erection, the team describes the project as a Herculean effort.
Bargmann echoes this sentiment: “Necessity is the mother of invention. This was the only way to make it happen in a safe, cost-effective way.” And ultimately, exemplary projects don’t happen without enthusiastic clients. “The university should be congratulated for having the vision,” he says. Recognizing the project’s most innovative building and design, the Society of American Registered Architects granted it a 2019 Nation Design Merit Award.