Structural Engineering Award of Excellence: 35 Hudson Yards, New York City
Charles Besjak
Director of Structural Engineering
Skidmore, Owings & Merrill LLP, New York City
Strengthening Support Points For a Mixed-Use Program
The second-tallest tower in the massive Hudson Yards complex, the mixed-use program of 35 Hudson Yards consists of several restaurants, fitness amenities at the base, Equinox office floors, and a hotel and luxury residential condominiums above. The retail and office podium drops off at Level 14, leaving a relatively square floorplate at hotel floors up to Level 30. Starting at Level 32, the southwest corner of the tower is chamfered, creating a terrace. Every ten floors, corners are chamfered in succession in a counterclockwise manner to create a series of residential terraces.
The structural design for 35 Hudson Yards needed to balance the many architectural programs of the building with the limited existing support points between railroad tracks. Site constraints informed the structural solution, which included using a previously designed steel platform to overcome the lack of direct concrete connection to terra firma. In the east-west direction, the core walls align with the limited space available between tracks, allowing a narrow maximum width. In the north-south direction, the core spans 50 feet (15 meters) across three tracks, providing a clear span for the gym and office spaces in the lower levels, and transitioning to a more conventional 25 feet (7 meter) module for the upper residential two-way flat plates. The tower’s structural system consists of this high strength reinforced concrete core supplemented by a series of aligned buttress walls that extend to the building perimeter. The tower’s structural columns also align with the narrow steel columns that support the platform. By using high strength concrete with a design strength of up to 14 ksi, the team was able to limit the thickness of the building’s structure, lighten loads on the platform, and create smooth transitions as the tower rises in a series of setbacks.
