2005 Platinum Award for Engineering Excellence. ACEC New York

The Attacks of 9/11 destroyed a major part of the television and Radio antennas that served the larger New York area.  In the aftermath a consortium of Television and Radio stations began soliciting proposals for a 2000 SF tall tower to replace the missing infrastructure. The site under consideration were varied and included Governor's island Manhattan and several sites in New Jersey.  We were approached by a group hoping to promote a site adjacent to the Liberty Science Center.

The site provided an open area, in the immediate proximity of New York City and adjacent to a major Science Museum. Hoping to tap into the potential of a radio tower as an attraction for the Museum the client wanted to include public spaces, including a viewing platform in the tower.

We worked very closely with Gilsanz Murray Steficek to design something that could be built with concrete and without guide wires, therefore minimizing the footprint of the building and the required site dimensions. 

Our strategy was to create a building with mass but also as efficient and stable of a structure as possible. We also wanted to create an iconic structure with a sculptural form that engages viewers. Starting with the fact that the minimum stable footprint needs three points of support we quickly came up with the braced tripod as a basic structural element.  The tripod is an ideal form because it places the mass of the structure as far as possible toward the edge making a stiff and stable structure- the widest stance possible on the least number of legs. By essentially creating three tripods stacked on top of each other and rotating the triangular plan at the base and top of each tripod we were able to create a stable structure that is very rigid and stiff.  

The shifting geometry is key to the design. It provides more balanced wind resistance by presenting a different shape to the wind along the full height. This helps in particular with vortex shedding. Visually this translates to a sculptural, dynamic visual presence.  As a viewer moves around the tower, the relationship between the pieces changes.  It goes from a  symmetrical stable appearance to a very asymmetrical and unstable appearance.  

The fact that the lateral forces on the top and bottom of the tripod structure had to be resisted provided us with the opportunity to create floor plates at these levels that simultaneously tied the structure together and provided the occupiable spaces that our client required. These platforms are triangular in shape and are connected to each of the tree legs.