Beacon News

NYC Construction Industry News: One Manhattan West Employs Unique Concrete Core Design on Challenging Site

Beacon's NYC office is just a few blocks away from some of the most amazing skyscraper construction projects underway in the U.S. One building our team has enjoyed watching rise two blocks west of Penn Station is One Manhattan West, a 995-foot-tall tower which was topped out in September of 2018. A unique aspect of the building is its reinforced-concrete core design.

According to the firm which designed the building, Skidmore, Owings & Merrill (SOM), the concrete core design was the solution to the project's most challenging aspect—being built directly above New York City's active west side rail lines which lead to Penn Station.

According to a July 2018 article by architect Julia Murphy of SOM on the website, the site had a limited amount of space to anchor the building to solid ground. That, combined with the close proximity of trains, made it impossible to support the tower on conventional columns. Thus, the concrete core design was the solution to site-specific challenges, but also provided many benefits in terms of having huge floors which are nearly column free and an amazing glass-enclosed lobby which reveals the tower’s structural core rising from the ground like a massive tree trunk.

Navilus Contracting, one New York's leading concrete superstructure contractors, built the concrete core for the new 67-story, 2-million-sf office tower. The core of the building was topped out in June of 2018. It was built ahead of the structural steel skeleton and the concrete floor slabs. The buildings exterior steel structure was topped out in September of 2018.

In a recent article on the website, Navilus Vice President Peter Downes explained how the central core was built. According to the article: "The concrete core is like the spine of the building and the steel beams for the floors are connected from the concrete core to the perimeter columns. This makes the structural skeleton of the building." In simplified layman's terms, Downes compared the design to an artificial Christmas tree where you build the pole in the middle and then hang the branches off of it. Metal decks are placed on the structural steel beams and concrete is poured on the decks to complete each floor.

In addition to being the "backbone" of the building, the concrete core houses the elevator banks and stairwells. The core is truly a building within the building and provides additional protection in case of an emergency and occupants need to use the stairs to leave.

The images below show the building during differenct phases of construction. If you find yourself in NYC with an hour of free time, a walk along Manhattan's elevated "High Line" park will give you wonderful views of One Manhattan West and other incredible buildings under construction nearby.

Image 1: One Manhattan West (photo taken late November 2018).
Images 2-3: November 2017 - The reinforced concrete core rises ahead of the surrounding structural steel.
Image 4-5: March 2018, a view of One Manhattan West from the High Line.
Image 6 (April 2018) & Image 7 (May 2018): The core has risen quickly above the surrounding buildings.
Image 8: August 2018 - Getting close to topping out the exterior structure.