Waterline Square, a 2.3 million square feet complex by Boston-based GID development group is the crown jewel of the Riverside South Redevelopment, a 77 acre 22 building masterplan realized over the last thirty years stretching from 59th to 72nd Street on Manhattans west side. The site comprises three Starchitect projects enveloped by a shared podium at grade and below.
The design architect of 1 Waterline Square was Richard Meier, a forty-story tower reaching 460 feet. The main architectural feature of this building is the iconic sawtooth profile on the north façade with column-free spaces for terraces at the 14th and 29th floors achieved by large walking columns and “hung” slabs/columns where required. Two 20-feet deep transfer beams from the 2nd to the 4th floor span 68 feet to pick up the loads of the tower columns above leaving only four columns below.
Two Waterline Square, designed by KPF Architects, is a 1.2 million square foot residential building formed by a podium and two towers. The West Tower has 39 stories and a height of approximately 456 feet. The Tower has 27 stories and a height of approximately 300 feet. Both towers feature sloping top-of-house levels and will be interconnected below the 12th floor by a podium. The most distinctive aspect of the project is the presence of two significant cantilevers. One is 25 feet at the 13th floor and extending the overhanging to the top of the west ring beam at the highest point of the building. The second cantilever, 25- feet long, is located at the 7th floor and extends to the top of the podium at level 12.
Three Waterline Square was designed by awarded and renowned architect Rafael Viñoly standing 34 stories tall. One of the most iconic features of this buildings is that all exterior columns are sloping from the first to the top floor, resulting in not two floor plates being the same. The structural design had additional challenges as most columns slope in two directions. The most significant load pickups in the building is at the 23rd floor where a column is picked-up by four cantilevered concrete-encased W36x800 steel beams.
All 2.3 million square feet is solely cast in place concrete construction (up to 12 ksi) and showcases unique structural solutions to address the extreme variation in floor plates, hundreds of columns shifting regularly up the structure, expansive column-free spaces at and below grade and all without introducing additional materials or construction methods. Perhaps the most elegant feature of the project is a new landscaped park and underground amenity space articulating all three buildings into one unified project. The double and triple height column free below grade spaces provided its own set of challenges with clear spans up to 60 ft, the complexity of which was amplified by the fact the heaviest loading in the project (fully landscaped park) was over these long spans.
This presentation will highlight some of the notable features, challenges and unique structural solutions.