Have you ever noticed the structural material of stair wells? They are usually made of concrete or masonry.
Ours is different in that its structure (the walls) are made from seven-layer Cross Laminated Timber (CLT) panels that are over eight inches thick, eight feet wide, and three stories tall.
Using CLT in this way allows us to employ the stair walls for structural support to resist wind and seismic (i.e. lateral) forces. Two stair wells, one elevator shaft and four service shafts, all distributed throughout the North and East parts of the building fulfill this function.
There are interesting details to discover in these stair wells.
- Base hold-downs. These are 10-foot long steel plates that are glued into the edges of panels.
- Structural beams and drag struts that tie into these walls. These penetrate through the walls at various locations.
- The fourth story add-on in the West stair well. Because CLT panels were three stories tall (for transportation), one-story panels needed to be added.