“Experimental cyclic tests on cross-laminated timber panels and typical connections.”

Cross-laminated timber panels (X-LAM) are used more and more as construction material for buildings. Since such panels are fairly stiff in their plane, particularly when obtained by gluing adjacent layers of planks, they cannot dissipate significant amount of energy during an earthquake. The mechanical connections between adjacent panels and with the foundations hence become the most important component affecting the static and cyclic behaviour of X-LAM buildings. For a reliable seismic analysis, therefore, it is crucial to investigate the cyclic behaviour of the connections between wall panels. An extended experimental programme on typical X-LAM connections was performed at IVALSA Trees and Timber Institute. Shear and pull-out monotonic and cyclic tests were carried out on holddowns and steel angle connectors used to anchor the wall panels. In-plane shear tests were also performed on mechanical screwed connections between adjacent X-LAM panels. In addition, cyclic tests were carried out on full-scale single and coupled cross-lam wall panels with different configurations and mechanical connectors subjected to lateral force. The paper discusses the results of these tests in terms of strength, stiffness, energy dissipation, impairment of strength and ductility. A comparison between test results and a simplified analytical calculation method is also provided. The overstrength factor, which is of great importance in capacity based design, was also evaluated for the different types of connection tested.