STRENGTH AND STIFFNESS OF GLULAM TRUSSES WITH PUNCHED METAL PLATED JOINTS

Several Canadian wood truss manufacturers expressed a need to develop technical information to initiate the fabrication and acceptance of wo od trusses made with glued-laminated timber (glulam) members and conne cted by punched metal plates. In collaboration with industrial partici pants, Forintek Canada Corp. developed a program for testing and analy sis of metal plated glulam trusses. Twelve 3/12 pitched chord trusses and three parallel chord trusses, all 13.7 m long, were designed by th ree different plate manufacturers. All truss fabrication took place at a single truss manufacturing plant. Trusses composed of 79 mm wide an d 152-229 mm deep glulam members connected by 16-gauge punched metal p lates were tested to failure. The ratio of ultimate to design load ave raged 3.5, and varied between 2.7 and 4.4. Both wood and plate failure modes were observed. The results suggest that the sizes of glulam mem bers used in this study are structurally suitable for use with 16-gaug e metal connector plates.