Numerical parametric study of cross-laminated timber diaphragms under in-plane loading

Cross-Laminated Timber (CLT) is a mass timber product that has gained recognition as a viable structural product for tall and large structures. While CLT provides several advantages, such as being eco-friendly, lightweight, and improving thermal insulation compared to other primary structural materials, its application in the horizontal diaphragms, specifically for floors and roofs, has not been thoroughly investigated. This paper presents the development of a detailed finite element (FE) model capable of simulating the response of CLT diaphragms under in-plane loading. The accuracy of the developed models was evaluated through comparison with available experimental data. Additionally, a comprehensive parametric study was conducted to examine the influence of various factors, including connection stiffness, boundary condition, panel installation pattern, and panel thickness, on the in-plane deflection of the CLT diaphragm. The research indicates that panel-to-panel connections play a more critical role in determining the stiffness of CLT structures than panel-to-beam connections. Furthermore, it was demonstrated that the deflection of CLT panels was influenced by different parameters depending on the orientation of the applied load. When the load is applied perpendicular to the panel length, panel thickness influences the diaphragm deformation. Conversely, when the load is applied parallel to the panel length, the panel-to-panel connection stiffness has a more significant effect on the deformation of the diaphragm. Findings also revealed that staggered CLT panel layouts provided more load distribution and higher capacity compared to non-staggered layouts when the load was applied perpendicular to the panel length.