Capacity-Based Design for Cross-Laminated Timber Buildings

The use of cross-laminated timber (CLT) in residential and non-residential buildings is becoming increasingly popular in North America. While the 2016 supplement to the 2014 edition of the Canadian Standard for Engineering Design in Wood, CSAO86, provides provisions for CLT structures used in platform type applications, it does not provide guidance for the in-plane stiffness and strength of CLT shearwalls. The research presented in this paper investigated the in-plane stiffness and strength of CLT shearwalls with different connections for platform-type construction. Finite element analyses were conducted where the CLT panels were modelled as an orthotropic elastic material, and non-linear springs were used for the connections. The hysteretic behaviour of the connections under cyclic loading was calibrated from quasi-static tests; the full model of wall assemblies was calibrated using experimental tests on CLT shearwalls. A parametric study was conducted that evaluated the change of strength and stiffness of walls with the change in a number of connectors. Finally, a capacity-based design procedure is proposed that provides engineers with guidance for designing platform-type CLT buildings. The philosophy of the procedure is to design the CLT buildings such that all non-linear deformations and energy dissipation occurs in designated connections, while all other connections and the CLT panels are designed with sufficient over-strength to remain linear elastic.