Mechanical behaviour of multi-panel cross laminated timber shear-walls with stiff connectors

Multi-panel Cross Laminated Timber shear-walls with stiff vertical joints may represent a valuable structural solution for multi-storey timber buildings in low seismic prone areas. In this study, the opportunity of using shear-key connectors in the assemblage of stiff vertical joints as an alternative to short-spacing traditional dowel-type mechanical fasteners is evaluated. The mechanical behaviour of two types of stiff shear-key connectors is investigated through an experimental campaign conducted at joint and wall level. Shear tests were firstly carried out to determine the mechanical properties of panel-to-panel joints assembled with the shear-key connectors. The results are compared with those obtained from shear tests on joints with screwed connections (half-lap and spline joints). Full-scale shear-wall tests were then performed to determine the mechanical performances of the con-nectors at wall level. Joints with a single shear-key connector showed values of stiffness and strength comparable to those that would be obtained for vertical spline joints with approximately thirteen couples of 6 mm screws. The failure modes on the joints with shear-key connector were characterized by either a localized crushing in the wood or the shear failure in outer lamination of the CLT panels with no plastic deformation of the connectors.