Innovative shear keys for resilient CLT rocking walls: Full-scale experimental testing and design method

CLT rocking wall systems are increasingly being adopted as lateral load-resisting systems in seismic regions due to their numerous advantages and benefits. As wall hold-down designs advance toward ductile fuses and resilient joints, there is a growing need for diaphragm wall-to-floor connections to evolve beyond conventional bracket and fastener systems, where the connection must facilitate large wall uplift demands and accommodate free rocking of the wall while reliably transferring horizontal forces and allowing the wall to undergo repeatable cycles without loss of strength or stiffness. This paper presents two innovative shear keys that provide complete force and displacement compatibility between the rocking walls and the diaphragm (gravity frame), both in-plane and out-of-plane. The performance of these shear keys is presented and assessed as part of full-scale experimental tests of a resilient two-storey CLT wall structure, and the design methodology and considerations for both shear keys are described in detail. Cyclic quasi-static test series are conducted to drift levels of up to 4%, and both shear key configurations maintained continuous and adequate horizontal force transfer throughout the testing programme. This enabled the cyclic damage free performance of the resilient structure while demonstrating resilient characteristics, with the shear keys remaining elastic and free from damage (or yield) throughout the test series. The proposed shear keys have the potential to complement recent developments in innovative and advanced rocking systems that are increasingly being adopted in projects worldwide where resilience and performance based design are key objectives, for both new construction and retrofit applications.