ObjectiveThe appearance of CLT (cross-laminated timber) enables wooden buildings to break through height limitation, yet the current use of metal connectors reduces the efficiencies of CLT and wastes the mechanical capacities of CLT. Thus, the study of CLT connections becomes a vital issue. In order to provide scientific basis for the engineering application of mortise-tenon connection in CLT building, this paper makes a study of the shear performance of the mortise-tenon connection, and compares it with self-tapping screws (STS) used for wall-to-wall joints.
MethodH-type CLT specimens connected with STS and mortise tenons were subjected to monotonic and cyclic loading test. Load-displacement curve, hysteretic curve and skeleton curve under pure shear loads were obtained. Mechanical properties such as initial stiffness, peak load, energy dissipation, stiffness degradation and strength degradation were investigated combining failure mode.
ResultIt was shown that STS connections failed before the damage of CLT material appeared, and the damages also occurred on the wood around connections. While mortise-tenon connections failed after the damage appeared of CLT. In monotonic loading tests, mortise-tenon connections presented lower ductility than STS connections, but maximum load, ultimate displacement, yield load, yield displacement and energy dissipation were higher than STS connections by 313.50%, 35.38%, 370.80%, 92.76%, 459.64%, respectively. In cyclic loading tests, the ductility of STS connections deteriorated, but that of mortise-tenon connections became better. Meanwhile, the maximum load of pushing and pulling phase of mortise-tenon connections were respectively 455.54% and 234.74% higher than STS connections, and its ability to maintain stiffness, strength and consume energy were all better than STS connections.
ConclusionCompared with the STS connections, mortise-tenon connections can allow full use of the strengths of CLT material and promote engineering application of CLT building.