Thornton Tomasetti, New York City
With cities vastly growing and densifying, building over existing infrastructure is providing opportunities for large developments in prime areas that were previously seen as difficult to utilize. Hudson Yards is the centerpiece of New York City’s redevelopment of Manhattan’s West Side. A 18-million square foot commercial and residential development constructed over a 32-acre, six block site over the Long Island Rail Road yards and facilities, Hudson Yards will become a city within the city in the largest private real estate development in the history of the United States. The eastern Phase with four tall commercial and residential towers is anticipated to be completed in 2019 and were constructed over the operating rail facility. Specialized solutions were developed to support the towers addressing site conditions including existing tracks, tunnels, buildings, and utilities. The centerpiece tower, 30 Hudson Yards, rises 1300 feet and includes 2.8 million gross SF of office space with an additional 1 million gross SF of retail space in its adjoining podium. The building contains systematic structural transfers joining the grid of the building above with the column grid below, which is dictated by limited options for column supports within a web of existing tracks and utilities underneath. Rising from these lower level transfers, the building transitions from a side core at lower floors of the building to a center core for the remainder of the tower. Steel braced cores are utilized to minimize self weight imposed on the transfers and caissons below. Multiple outrigger levels are strategically placed within the tower to engage perimeter columns in lateral load resistance.