Numerical assessment of the cyclic behaviour of multi-panel CLT shear walls in platform construction

Multi-panel (MP) CLT shear walls in platform-type construction can be efficient seismic force resisting systems (SFRSs) for low-rise and mid-rise mass timber buildings. This paper presents a capacity-design (CD) framework for MP CLT shear walls, comprising design principles, a stepwise design approach, and rational capacity protection factors (CPFs) to ensure a clear yielding hierarchy under lateral loading. An experimental database of CLT connections was used to calibrate and validate numerical models using the HYST algorithm, a mechanics-based, protocol-independent subroutine. These models were then implemented in the finite element (FE) program CLT-WALL2D to evaluate wall behaviour through quasi-static cyclic analyses. Two case-study buildings were designed based on the proposed framework, and the numerical results indicate that the investigated walls can develop ductile cyclic responses and energy dissipation. Parametric studies on CPFs highlighted their influence on the load-displacement response and energy dissipation. The reported CPF values are limited to the investigated connection configuration and prototype cases, and broader calibration is required before generalized design values can be recommended. However, establishing the yielding hierarchy poses some challenges, requiring careful balancing of connection strength and stiffness characteristics. Proper design of hold-downs is also critical to ensure favorable kinematic mechanisms. The study provides valuable insights into the issue for optimizing MP CLT shear walls and emphasizes the importance of implementing CD principles in the seismic design of platform-type CLT walls.