The TallWood House at Brock Commons is an 18-storey mass timber hybrid building at the University of British Columbia (UBC) in Vancouver, Canada. Reaching 53m, this student residence building has been recognized as the tallest mass timber hybrid building in the world. It is comprised of 17 storeys of five-ply cross laminated timber (CLT) floor panels, glue laminated timber columns, and a concrete transfer slab at level two. Two full height concrete cores provide the lateral stability.
The engineers developed a series of standardised components that reduced the number of elements over conventional timber framing systems and hence reduced the frame erection time to just nine weeks. They carried out full scale testing with the University to understand the interaction between the various materials and components to demonstrate the capacity of the system and gain the associated Government regulatory approvals.
The engineers developed this innovative solution to deliver a highly economic and sustainable alternative to more traditional construction methodology. The judges were unanimous in their admiration for the fresh approach that was taken across design and detailing, which has developed an economic new hybrid system for high rise structures and set a new precedent for what can be economically achieved in predominantly timber structures.
The engineers worked with the CLT supply chain to demonstrate sufficient two-way spanning action in the floor panels to remove the need for supporting beams: with each panel support directly onto timber columns at their corners. A steel spigot detail was developed to transmit column axial forces and support the panels. The engineers carried out FE analysis of the laminated timber panels and full scale physical testing to demonstrate punching capacity in excess of the standard code guidance. The use of concrete cores for economy, combined with the timber columns, required a detailed analysis and adjustments to predict and mitigate against the relative differential shortening due to strain, shrinkage and creep. Monitoring has been carried out to understand the behaviour of the frame in use.