As part of a masterplan along the Chicago River, the River Beech Tower is a residential high-rise which, if built, would be taller than any existing timber building. The collaborative team behind River Beech consists of architects Perkins+Will, engineers Thornton Tomasetti and the University of Cambridge. Currently a conceptual academic and professional undertaking, the team state that it could potentially be realized by the time of the masterplan’s final phases.
The team believes that they will be able to “reach far greater heights than any existing timber building” using only “real, commercially available timber materials.” Existing timber skyscraper proposals come in at around 30-40 stories, such as C.F. Møller and DinellJohnasson’s 34-story residential building in Stockholm, set to be completed in 2023. SOM have also developed a system that shows the possibility of a 42-story building as part of their Timber Tower Research Project. Completed or soon-to-be complete timber buildings stand a little shorter, with Acton Ostry Architects’ 18-story student residence currently under construction in Vancouver and the 10-story Forte apartment building in Melbourne.
Structurally, these existing buildings make use of a hybrid system of engineered timber (cross-laminated and glulam) and concrete (often in the core), to achieve their heights. Slightly different to these systems is Michael Green’s "Finding the Forest Through the Trees" (FFTT) construction model, which has a wooden core and wooden floor slabs, with steel beams to provide ductility--essentially, as steel is able to stretch more than wood, these beams hold the structure together under extreme lateral loads such as in an earthquake or high winds.
The River Beech team however, use a different system entirely, and credit this innovation as their key to new wooden heights. The system engages an exterior diagrid system, taking advantage of the natural axial strength of timber. The building’s vertical and lateral loads are resisted by connecting the outer diagrids with the internal cross bracing that skirts the central atrium, allowing for efficient load distribution across all timber elements.
At 80 stories tall, the conceptual brief caters for 300 duplex units and multi-story penetrations that form communal spaces. The play between private and public within a carbon-neutral structure ties together the team’s vision of their “social and sustainable adaptation to high-rise development.”
Perkins+Will Project Team: Ralph Johnson, Todd Snapp, Jeff Sanner, Rachael Bennett, Gilryong Song
Thornton Tomasetti Project Team: David Weihing, Edward Peck, Alejandro Fernandez, Mark Chiu, Timothy Wong
University of Cambridge Project Team: Michael Ramage, Rob Foster