Aluminum alloy connectors were developed and applied to cross-laminated timber (CLT)
connections with fasteners of self-tapping screws (STSs) in this study to investigate the effects of
connector types, and the diameter and number of STSs on the shear resistance performance of CLT
connections. The CLT of heterogeneous-grade construction was made using Cryptomeria japonica
plantation timber mixed with southern pine (Pinus spp.). Effects of the different loading directions
along the wood grain were also considered. Results showed that maximum shear capacities of
CLT connections assembled with T-type and plate-type connectors were 51 and 43%, respectively,
higher than that of a CLT connection with angle bracket connectors. The initial stiffness of the CLT
connections assembled with these 2 types of connectors was also found to be 2.8- and 6.1-times
higher, respectively, than the CLT connection with angle bracket connectors. Both the maximum
shear capacity and the initial stiffness of CLT connections fastened with 6-mm STSs increased 47
and 42%, respectively, as the numbers of STSs applied increased from 18 to 28 during connection
assembly. Increases of 34 and 61% in the maximum shear capacity and initial stiffness, respectively,
of CLT connections were found as the numbers of 8-mm STSs applied increased from 12
to 18. It was also found that the shear resistance performance of a Japanese cedar CLT connection
was close to that of a southern pine-mixed CLT connection. A higher maximum shear capacity and
yield shear capacity of a CLT connection were found only in the case fastened with 28 6-mm STSs
when the loading direction was applied perpendicular to the wood grain at the connection instead
of parallel to the wood grain. The average energy dissipation of the CLT connections increased
59% when a connector was assembled with more STSs. Ductility ratios between 2.2 and 8.4 were
obtained when CLT connections were assembled with aluminum alloy connectors using selftapping
screws, and the most ductile behavior was found for a connection assembled with plate
connectors.