Mechanics-based analytical models for balloon-type cross-laminated timber (CLT) shear walls under lateral loads

Besides platform-type construction method, a rarely investigated balloon-type method, in which the walls are continuous for the entire height of the building and the floor panels are attached to the walls at each floor, can also be used to construct Cross Laminated Timber (CLT) buildings. The balloon-type method endures several key advantages to the CLT buildings, such as reducing connections and avoiding accumulating compression perpendicular to grain in the floors, thus being a viable solution for high-rise buildings. In this paper, two mechanics-based analytical models (rigid- and elastic-base models) were developed for predicting the deflection and resistance of balloon-type CLT shear wall system. The developed analytical models incorporate the contribution of the wall bending and shear deformation, as well as contribution from the wall rocking and sliding, and the slip in the vertical joints between panels, on the overall wall deflection. The resistance of this system was assumed to be governed by the hold-downs, shear connectors, and vertical joints, if present. The analytical models were validated against the test results of four balloon-type CLT shear walls in two configurations tested under monotonic or cyclic load. The verified analytical models were used to investigate the influence of vertical load, wall aspect ratio, and vertical joint on the structural performance of the balloon-type CLT shear wall. The developed analytical models provide a mechanics-based approach for researchers and engineers to predict the structural performance of balloon-type CLT shear walls. The wall test results and the parameter analysis results gave a valuable insight into the structural behavior of the balloon-type CLT shear walls.