Cross-laminated timber (CLT) panels are increasingly used in floor construction with the individual panels often connected with self-tapping screws (STS) through surface spline, half-lap, and butt joints. An alternative solution is provided by using the Timber Structure 3.0 (TS3) technology that connects butt joints through high-performance adhesives and creates a near-rigid connection; therefore, two-way resistance of CLT panels can be utilized. However, TS3 joints fail in a brittle manner, and floor diaphragms lose integrity after crack develops. In this study, measures to improve the robustness and prevent floor collapse after TS3 joint failure were investigated. Seven panel-to-panel connections with TS3 and a secondary connection system were fabricated and tested under bending to evaluate the joint behaviour and observe crack propagation. After TS3 failed, bending or shear tests were conducted to test the residual strength of the secondary connections. The tests showed that it is possible to increase the robustness of TS3 joints by using additional mechanical connectors; i.e., the secondary connections exhibited residual strength after the TS3 joints failed. More tests are planned to further investigate measures to improve the robustness of TS3 joints.
