Photo Courtesy Of CetraRuddy

The $140-million 620-ft-tall condominium tower is built on a poured-in-place concrete structure wrapped in a glass and aluminum hybrid curtainwall. The building includes several 4- to 6-story “pods,” which cantilever to the north and east of the building.

Working on a 5,175-sq-ft footprint at the busy intersection of Madison Avenue and East 23rd Street, logistics presented the greatest challenge for construction crews, says Gerald Bianco, project executive and senior vice president at New York-based Bovis Lend Lease, the general contractor.

“We had a crane in the front, a hoist in the back and we squeezed a loading dock in by the crane as best we could,” Bianco says. “Trucks had to back in from the intersection to the site. To some extent the logistics made a lot of the decisions for us.”

The project was sequenced in two phases with a second phase that consisted of a five-story add-on to the podium of the tower. To keep the project on schedule, phase two was executed while phase one construction continued. A heavy-duty cantilever platform was built on the east side to protect workers on the phase two portion of the building.

The slenderness of the tower required designers to optimize internal sheer walls that worked with the building floors. A system of tuned liquid column dampers was added to the roof to minimize lateral and seismic forces. The system is comprised of three cast-in-place reinforced concrete tanks filled with water and incorporated in the building structure at the roof level.

The design team also added perimeter walls and a ring beam to the roof, 580 ft from the ground. To form and pour the ring, the project team had a scaffolding system built on cantilevered beams from the 50th floor that encased the building on all four sides and rose 45 ft so that crews could safely work on the perimeter wall and ring beam.

The project was one of the first of its size in New York City to use a vertical netting system—or Cocoon—at the forming floor to protect workers and material.

With its slender style and pods that maximize views of the Madison Square Park area, the tower brings a modern look that aims to compliment neighboring historic spaces, such as the 101-year-old Met Life Tower, says John Cetra, founding principal of New York architecture firm CetraRuddy.

“There was a lot of innovation used here in terms of creating a building that maximizes all of the views,” he adds. “At some point all of that fades into history, but the building stays there. The way that it relates to the area and the towers around it, that’s the thing that makes me excited.”

Key Players

Developer/Owner: Slazer Enterprises LLC
GC/CM: Bovis Lend Lease, New York
Architect: CetraRuddy, New York*

*Submitted Project to New York Construction