Abstract
In this study, a symmetrical mixed-grade composition glulam was fabricated using 37~39-
yr-old Japanese cedar plantation timber. A full-size portal frame was then constructed with
two 140×304.8×2200-mm posts and a 140×304.8×3000-mm beam to investigate the resisting
performance of the frame system to lateral forces. Each joint between the glulam beam and
post members was assembled with a design L- or I-type metal connector with 2 placement
types using 8 pin fasteners. The glulam portal frame was subjected to a rack test with 7 stages
of a lateral cyclic loading protocol and a monotonic loading application. Results indicated that a 12.7% increase in the maximum lateral load capacity was found for the glulam portal frame
using a straight metal connector with pin fasteners arranged in a square compared to fasteners arranged in a circle. Also, the portal frames assembled with fasteners in the square placement
for both the L- and I-type connectors showed 20.6~36.4% higher initial stiffness and dissipated energy values than those in the circular arrangement. The reference shear strengths of the
Japanese cedar glulam portal frames were 9.6~13.7 kN, which were derived from critical
P1/120 values among all connector and fastener placement conditions. These reference
shear strengths of glulam portal frames were 19.8%, on average, of the maximum lateral load capacity. Resultant multiplier parameters of the shear wall were 2.33~3.35, and better structural performance was found for portal frames assembled with the L-type connector and pins
arranged in a square.