Waterline Square

Owner: GID
One Penn Plaza, 250 West 34th Street, 2nd Floor, New York, New York

Architect: Hill West Architects, KPF, Richard Meier, Vinoly
Engineer: WSP
Construction Management: Aecom/Tishman
Concrete Contractor: Pinnacle Industries (WLS2) & Sorbara (WLS1 & WLS3)
Total Project Cost: $2.3 Billion
Total Project Size: 2.12 Million (3 Towers + base)
Building Height: 460 Ft
Number of Floors: 40
Reinforcing Tons: 12257
Total Concrete Yards: 96,818


Sitecast two-way flat plate system. The main design challenges were related to the location of the project, the irregularity and non-repeatability of structural elements and the programmatic requirement for either large column-free zones (such as the below grade basketball court and drive isle at the ground floor), and the multi-story spaces the largest of which covers four floors (40 feet). The morphology of the buildings, combined with the programmatic requirements and multiple geometric irregularities translate to structures with extreme variation. For example, in Two Waterline Square, 35 out of 40 floors present distinct floor plates, resulting in almost all 235 columns of the buildings changing location at least once.


Flexibility, both in terms of the natural progression of a fast-track project as well as the inherent ability to efficiently address the complex morphology and countless unique conditions throughout the site. There are no typical floors, the entirety of the 2.3 million square foot site is comprised of unique floor plates and hundreds of columns continually shifting locations, sloping in one or multiple directions, being picked-up, being hung, rising up to 60 feet without lateral bracing, combining, splitting, etc. Furthermore, 60 feet spans over double and triple height amenity spaces, massive sections of building cantilevered over the plaza, and 20 foot transfer girders were necessary, so the selection of cast-in-place (CIP) was quite evident in consideration of its versatility to handle these diverse conditions.

Waterline Square 1 (designed by Richard Meier): Most notable structural feature is the iconic carved-out north facade with column-free spaces at the 14th and 29th floors achieved with walking and hung columns (Figures 1 and 2). Two 20-ft deep transfer beams span 68 feet to pick up 11 tower columns leaving only 4 columns at grade.

Waterline Square 2 (designed by KPF): In addition to the sheer scale of a 1.2 million square foot building with 17 setbacks and 200 columns (Figures 3 and 4) there are two significant cantilevers: West portion of the west tower cantilevers 25 feet from the 13th floor to top of the building (40th floor) and the southern cantilever which is also 25 feet from the seventh floor to top of the podium at 12th floor (Figures 5 and 6). A system of sloping ring beams supporting the façade extension at the top of both towers rises 50 ft unbraced at the high point comprised of sloping trapezoidal beams to maintain a planar top surface (Figures 7, 8 and 9).

Waterline Square 3 (designed by Rafael Viñoly): The most distinctive feature is the pyramidal morphology supported by columns from ground to top of building which all slope in multiple directions (Figures 10 through 13). There is a significant pickup on the 23rd floor to allow a column free exterior terrace.


In addition to being the material of choice for NYC residential structures, the 19 previous buildings of the development were cast-in-place CIP concrete, both ownership and the CM expressed a desire to stay within the confines of what has worked well for the site. As a fast-track project with an aggressive schedule, CIP offered the flexibility for the project to evolve even as foundations and lower floors were being cast. In light of the scope of the project, both ownership and the Construction Manager were also strongly opposed to introducing any additional materials or construction methods in addition to CIP (steel, PT, etc.) to eliminate the challenges that come with mixing different trades.