This new, 32-story residential tower in New York City replaced a lot that sat vacant for two decades. The project site, located on a downtown corner of a popular city park, had been used as a car lot and was an eyesore compared to neighboring buildings in the Landmark District.
When the architect for the residential portion of the tower was approached about the design of the tower, they initially only had permission for an inexpensive-looking glass and metal building. However, the team soon reevaluated this decision. Owing to its prominent location, they decided they needed a design that would adhere to Landmark Preservation Commission conditions, which required that the new structure relate to surrounding buildings, either materially or in articulation.
This decision lead the team to a precast concrete design that used architectural precast concrete elements to mimic the historic architecture of the New York neighborhood within a reasonable budget. The precast concrete producer worked directly with the architect and the developer in a design-assist relationship for seven months during the development to perfect the unique tower design.
The facade was inspired by surrounding masonry buildings faced with limestone, red granite, Vermont marble, and black brick. The architect reinterpreted the aesthetic in a contemporary way by using precast concrete with flecks of marble and sandstone chips in various colors in a simple, rhythmic framework of column and lintel.
The precast concrete producer provided a polished finish on the face as well as on the returns of individual panels, including a consistent finish around corners. They achieved this by casting the return sides face-down, and then tilting them up and conducting a second pour to complete the front surface. The slab-edge elements received a polished finish on the soffit and front, whereas the top surface was sandblasted.
The appearance of the corner aggregates called for a sequential casting procedure to avoid a pour-joint line in the corner, combined with innovative mixture design and forming. The precast concrete producer developed a special polishing technique to achieve the desired polish depth and sharp edges; this method involved making numerous passes using various polishing pads with differing grits over the precast concrete panel.
The facades facing the park are characterized by floor-to-ceiling window openings and deep recesses articulated as Juliet balconies. Windows are supported by precast concrete elements that form a continuous external waterproofing layer, with joints easily accessible and maintainable throughout the building’s life.
Horizontal slab edges rest on the column covers, which transfer the dead loads back to the superstructure behind. The shallower side-facade elements combine multiple column and slab-edge elements, which were cast in a single pour, in a single unit.
To erect the structure in the busy New York neighborhood, the precast concrete producer developed a precise logistics plan for delivery and scheduled installation extending into nighttime hours. More than 1200 pieces were shuttled each night from the prefabrication facility to a drop lot in New Jersey. Then a contractor-supplied tower crane was used to install the pieces.
The carefully timed delivery and erection schedule allowed the team to meet the 120-day install schedule.