Approaches for Modeling the Rocking Base in CLT Balloon-Type Walls

This paper proposes both detailed and simplified approaches for modeling the base of cross-laminated timber (CLT) balloon-type walls. The timber at the base of CLT balloon-type walls is susceptible to delaminating and crushing due to the relatively high overturning moment demand under seismic or wind loads, especially in mid- to high-rise buildings. This complex nonlinear behavior at the base can significantly affect the wall’s performance under lateral loads and alter the demands on wall connections. Therefore, developing accurate models to capture the complex behavior at the base of rocking CLT walls is crucial. To achieve this, a detailed model of rocking CLT walls is developed in the ABAQUS software. Subsequently, a parametric study is carried out to investigate the effects of various parameters on responses, including (a) wall aspect ratio, (b) axial load, (c) wall thickness, and (c) hold-down strength. Pushover analyses are conducted to study the effects of these parameters on the overall base shear-top displacement curve, the variation in the base compression length, and the distribution of plasticity at the base of the wall. Following this, a simplified model is developed in the OpenSees software, which is more computationally efficient for future nonlinear time history analyses. The results demonstrate that the simplified model can accurately capture the local and global response of CLT rocking walls with acceptable accuracy.