Abstract
Structural symmetric glulam members which were manufactured from Japanese cedar plantation
timber were constructed into a box-type portal frame to investigate the moment-resisting
performance of the frame when subjected to a lateral load. The joints of the frame were connected
using aluminium connectors and self-tapping screw fasteners, and the placement of fasteners on
the connection was arranged into 3 patterns. The loading protocol was applied laterally in 7 cyclic
stages in the racking test. The results indicated that the maximum lateral load, yield lateral load, ultimate
lateral yield load, and initial stiffness of the portal frame fastened using self-tapping screws
and arranged in square placement were higher than those when using single-circular and doublecircular
placements. The resultant dissipated energy obtained from the portal frame with the square
pattern placement was 1224.2 kN·mm during the cyclic loading stages, which was higher than
the other fastener arrangement by 20%. Based on the criteria for evaluating the horizontal force
resistance of wooden wall structures, the allowable shear strength of the box-type portal frame was
determined by the load corresponding to the shear deformation of 1/120 radian. The frames could
provide a factor as a 4.4 of multiplier value when considered as a shear wall element. The equivalent
viscous damping of the box-type portal frames assembled with self-tapping screws was around 4%.