Feasibility Study of Mass-Timber Cores for the UBC Tall Wood Building

TLDR

The UBC Brock Commons building, completed in 2016, is a 53‑m, 18‑story hybrid wood‑based structure that uses a 17‑story mass‑timber superstructure supported by a concrete podium with two concrete cores for wind and seismic resistance. The objective of this research was to evaluate the possibility of designing the UBC Brock Commons building using mass‑timber cores. The study shows that mass‑timber cores, with appropriate design adjustments such as laminated‑veneer lumber and C‑shaped walls, can satisfy seismic and wind criteria, shorten construction time, reduce environmental impact, and offer potential cost savings.

Abstract

The UBC Brock Commons building in Vancouver, which comprises of 18 stories and stands 53 m in height, was at the time of completion in 2016 the world’s tallest hybrid wood-based building. The building’s 17 stories of mass-timber superstructure, carrying all gravity loads, rest on a concrete podium with two concrete cores that act as both the wind and seismic lateral load-resisting systems. Whereas the construction of the concrete cores took fourteen weeks in time, the mass-timber superstructure took only ten weeks from initiation to completion. A substantial reduction in the project timeline could have been achieved if mass-timber had been used for the cores, leading to a further reduction of the building’s environmental footprint and potential cost savings. The objective of this research was to evaluate the possibility of designing the UBC Brock Commons building using mass-timber cores. The results from a validated numerical structural model indicate that applying a series of structural adjustments, that is, configuration and thickness of cores, solutions with mass-timber cores can meet the seismic and wind performance criteria as per the current National Building Code of Canada. Specifically, the findings suggest the adoption of laminated-veneer lumber cores with supplementary ‘C-shaped’ walls to reduce torsion and optimize section’s mechanical properties. Furthermore, a life cycle analysis showed the environmental benefit of these all-wood solutions.