The residential tower with the striking surface built above New York City’s Museum of Modern Art was incredibly challenging to build. But William Kell, chief estimator at Sorbara Construction Corp., the superstructure concrete subcontractor on the 87-story, 730,000-sq-ft, cast-in-place building, says “our track record confirms that if a project is beyond a cookie cutter,” teams know to reach out to the Lynbrook, N.Y., firm.
The condo tower, named 53 West 53rd Street, earned ENR New York’s Project of the Year award for 2020 with its irregularly patterned, concrete diagrid exoskeleton designed by structural and mechanical engineer WSP USA. Design concept for the tower was by architect Ateliers Jean Nouvel.
“A significant amount of coordination had to be done when you consider a number of different technologies were used by the superstructure concrete contractor and the panelized curtain wall fabricator,” Hines managing director David Penick told ENR in November for the Project of the Year story. Hines developed the condo tower with Pontiac Land Group.
Kell, too, emphasizes the usual level of coordination required between many parties. His own role was essential; Kell bought the materials, hired vendors, handled daily issues with the concrete work and managed the project all the way through to close-out.
“The intersection of the diagrids created huge problems,” Kell recalls, like “fitting all the required reinforcing steel that met up” and connected many “sloping columns and slabs” at a single point. He brought in structural engineering consultant Steven Bongiorno to design those steel nodes.
Particularly difficult, Kell says, was that some of the nodes weighed more than 18,000 lb, and they “had to be installed prior to placing formwork, reinforcing steel and concrete.”
He notes the logistical challenge of building in midtown Manhattan on a tightly constrained site. “We placed all the concrete with a concrete pump and initially utilized a Liebherr 710 electric tower crane, then switched it out for a Liebherr 542,” he says.
Floor slabs became smaller and changed shape with each successive story. Each reused formwork from floor to floor, “but conditions were custom built,” Mark Lubrano, vice president and project executive at Lendlease Construction LMB Inc., the project’s general contractor, told ENR earlier. “Each floor was its own independent piece.”
Thanks to Bongiorno and Sorbara superintendent Tom McGeown cooperating so closely, Kell says, the team was “successful in topping off the superstructure weeks ahead” of its original 420-day schedule.”
The chief estimator credits the firm’s prior projects with preparing them for unusual challenges, especially its work on Frank Gehry-designed New York City buildings The Interactive Corp.’s headquarters and the Beekman Tower. “These two projects had his signature radical facades,” Kell says. But 53 West 53 imparted important lessons, too: “You have to assemble the best minds in the industry” to build such complex projects.