With the intense demand for high-rise buildings driven by global urbanization, architects keep pushing technology to conserve materials, increase efficiency, speed construction, and deliver more open, daylit spaces. To address these issues, Skidmore, Owings & Merrill (SOM) challenged the conventional model of tower construction: a perimeter moment frame tied by outriggers to an internal core tower with deep interior spaces. The firm’s research focuses on a common strategy employed in three competition tower schemes: the “tree trunk,” which proposes a structural supercore with cantilevered floors and a column-free perimeter. The projects are diverse in size, scope, and locale, and include the 25-story Takshing House Redevelopment tower in Hong Kong, the 110-story Fluidic Tower in Seoul, South Korea, and the 3,281-foot-tall (a)Spire Tower, designed for an undisclosed desert location. Each scheme enlarged and elaborated the structural concept.
In the case of the two larger towers, the supercore is built using concrete formwork technology that is both consistent and fast, typical of cooling-tower construction used in the nuclear power industry. Tapering as they rise, these internal core elements produce a maximum footprint and allow the building to transfer loads efficiently to the ground while accelerating the construction schedule. The large footprint of the supercore permits cantilevered floors—up to 40 feet for office-lease spans, less for residences and hotels. In addition to providing space for air movement and technical functions, the enlarged supercore offers “found” space that can be used as a place for meeting, gathering, shopping, and dining within the interior volume.
“I’m extremely jealous of what people who’ve been dabbling in high-rise buildings have been able to do,” juror Julie Eizenberg says. “The way that technology runs now and the way money is distributed, the real invention over the past five years has been significantly in towers. The other part that’s interesting is how few of them—excuse me, how none of them—is in the States.”
Project Tree Trunk Towers: Cantilevered Floor/Super Core Structure
Architect Skidmore, Owings & Merrill
Takshing House Redevelopment Brian Lee, FAIA, William F. Baker, James J. Pawlikowski, Thomas Kerwin, FAIA, David Krysak, Ame M. Engelhart, AIA, Craig Bahney, Henry Chan, Casey Renner, Yue Zhu, AIA (project team)
(a)Spire Tower Brian Lee, FAIA, William F. Baker, George J. Efstathiou, FAIA, Eric R. Keune, AIA, James J. Pawlikowski, Heather K. Poell, AIA, Casey Renner, Thomas Kinzl, AIA, Neil Katz, Craig Reschke, Weiqi Wang, Craig Bahney (project team)
Fluidic Tower Brian Lee, FAIA, William F. Baker, Jeffrey J. McCarthy, AIA, Eric R. Keune, AIA, James J. Pawlikowski, Thomas Kinzl, AIA, Michael Pfeffer, AIA, Casey Renner, Inho Rhee, Tatsuhiko Shibata, Chung-woon Jung, Kwangmin Kim, Aurelie Horn, Craig Reschke, Benton Johnson (project team)