Ronald McDonald House Willow

The world's tallest all-wood tower in a high seismic zone: Ronald McDonald House's Willow House in Vancouver.

While designers often use mass timber to resist gravity forces, Willow House will be, at the time of its construction, the tallest building in a high-seismic zone to use mass timber for gravity and lateral force resistance.

The first-of-its-kind lateral system will utilize coupled CLT shear walls linked with steel beams that are placed around the elevator and stair shafts of the tower to create a “core-wall” system. The steel beams serve as the seismic “fuses” for the CLT shear walls, which will be the first use of this lateral system worldwide. Continuous shear wall panels will span multiple storeys, with each lateral force-resisting element comprised of three or four prefabricated vertical panel segments over the building’s 12 storey height. Innovative connections will attach the panels vertically and horizontally, and high-strength, replaceable connections will enhance energy dissipation and ductility.  The CLT shear walls will provide a low damage and replaceable solution after a major earthquake by limiting residual drifts and allowing components to be easily inspected and replaced.

The feasibility of this system has been established through past full-scale testing, conducted by StructureCraft’s structural engineers during their doctoral theses, and project specific experimental testing and advanced nonlinear structural analysis are planned to validate the building design.
 
For the International Mass Timber Conference in Portland, StructureCraft and MGA had the opportunity to create a mockup of this innovative system. Notably, the mockup was entirely created by in-house carpenters with a combination of traditional craftsmanship and modern CNC machining techniques. 
 
Willow House will embody sustainability while creating a warm, restorative environment for families facing medical crises. The net-zero carbon building will feature studio, one- and two-bedroom suites with private kitchenettes, shared community spaces, and wellness programs. Willow House will stand as a legacy of care, resilience, and environmental responsibility.