Structural performance of balloon mass timber shear walls under in-plane lateral loads

Balloon-type mass timber shear walls are one of the most efficient structural systems to resist lateral loads induced by earthquakes or high winds. They are a viable solution for high-rise buildings, since they endure several key advantages, such as reducing connections and avoiding accumulating compression perpendicular to grain in the floors. This system, however, is not included in the 2020 National Building Code of Canada and has no design guidelines in the 2019 Canadian Standard for Engineering Design in Wood, so it is out of reach of most designers. A multi-year research project has been initiated at FPInnovations to quantify the system performance and develop the necessary technical information to codify balloon-type mass timber shear walls. This paper presents results of an analytical study on the structural performance of balloon-type CLT shear walls. A mechanics-based analytical model was updated to predict the CLT panel resistance, in addition to predicting the deflection and resistance of balloon type CLT shear walls. The influence of specific key parameters such as wall length and thickness, aspect ratio, vertical loads, and vertical joints, on the structural performance of this wall system under lateral loads was investigated using the updated model. The results of this study will give a valuable insight into the seismic performance of balloon type CLT shear walls.