OWNER & DEVELOPER: The Related Cos., NYC
OWNER: (offices): Bertlsmann/Random House Inc., NYC
ARCHITECT (core and shell): Skidmore, Owings & Merrill, NYC
ARCHITECT (residential): Ismael Leyva Architects, NYC
ARCHITECT: (residential): Adam D. Tihany International Ltd., NYC
INTERIOR DESIGNER: HLW International, NYC
STRUCTURAL ENGINEER: Thornton Tomasetti Engineers, Newark, NJ
MECHANICAL ELECTRICAL & PLUMBING ENGINEER: Cosentini Associates, NYC
GEOTECHNICAL ENGINEER: Langan Engineering & Environmental Services, NYC
SITE & SUBWAY ENGINEER: Vollmer Associates, NYC
STEEL ERECTOR & FABRICATOR: ADF Steel Corp., NYC
CONCRETE CONTRACTOR: North Side Concrete Corp., Bronx, NY
CONCRETE SUPPLIER: Quadrozzi Concrete corp., Rockaway Beach, NY
FOUNDATION CONTRACTOR: Urban Foundation/Engineering, East Elmhurst, NY
HOIST & SITE PROTECTION CONTRACTOR: Atlantic Heydt, Maspeth, NY
CONSTRUCTION MANAGER: Plaza Construction Corp., NYC

With spectacular views facing Central Park, the 675-ft., 50-story structure on Broadway in midtown Manhattan is remarkable in both its concept and execution of that concept.

This $180 million project is a true mixed-use project. It features two distinct structural elements, a 25-story corporate headquarters building for Random House that has been topped using a cantilevered platform by a 25-story luxury condominium tower, The Park Imperial.

Featured in its unique silhouette is a series of geometric angles with a tall central section jutting upward between two lower sections that, appropriately, resemble bookends. The profile of the building follows the diagonal of Broadway and the structure steps back twice, at the sixth story, atop the podium base, and again at the 26th story, the base of the residential tower. Above the 90-ft.-tall podium, the central portion of the building steps in and out vertically, a design that furnishes abundant surface area for the Central Park.

The project's two distinct structural elements posed the greatest challenge for the project's team.

The office structure has a structural steel frame and the residential portion has a concrete slab on concrete columns, creating a 27-story foundation for a 25-story building in the sky.

The primary structural task was to marry both frames. To achieve this, the 26th and 27th floors have to serve as transfer floors, where massive steel members transfer the concrete loads to the steel structure below. Because the layout of the residential tower is completely different from the layout of the office tower, there is no correlation between the concrete columns and shear walls and the steel columns below. Steel girders pick up the loads from the columns and carry them to a maze of trusses below. The girders, ranging in depth from 55 in. to 87 in., span to transfer trusses that also serve as outrigger trusses for the lateral load-resisting system. The trusses traverse the entire floor and connect to perimeter belt trusses that encircle the structure and help accommodate the load transfer. Thus, the trusses do double duty by carrying both gravity and wind loads.

As a tall and slender structure, the tower is subject to wind movement. Solely for the comfort of its occupants, the building features a tuned liquid column damper to limit the isolation of the building and regulate its movement. This is the first time a fluid mass tuned damper has been used on a structure in the U.S.

Because of the location of the structure, foundations required sophisticated underpinning techniques to support the adjacent buildings on minipiles at the west side of the site. This required drilling through water-bearing earth to rock from underneath the buildings. On the east side of the site, subway tunnels had to be braced under Broadway using caissons and traditional sheeting and shoring methods. At the center of the site, the location of the core footings, the ground inexplicably drops off, and the rock expected close to subgrade was not found. As a result, an additional excavation of 25 ft. to 30 ft. of excavation was required to reach sound bedrock.

The project's fast-track schedule and type of trades involved in the project called for careful planning and a great deal of coordination. This included bidding packages for long-lead trades early.

The intricate logistics of the construction process were simplified by using steel climber cranes, one of two used for steel erection, then by the concrete contractor, and back again. The crane was jumped at the completion of every two stories, and when the steel framing was completed, was raised to the 27th story, where it was slid along horizontal tracks to a position one bay south of the footprint of the residential portion, a feat rarely, if ever, performed on a structure in New York

Value engineering was implemented to save time and money. The choice of steel framing for the 27th floor, at the top of the transfer level, for example, rather than concrete beams or steel encased in concrete, was a result of that process.

The jury praised this project, calling it "a major mixed-use structure whose project team was challenged by site logistics, requiring a redesigned foundation as construction progressed."