Abstract
In this research, joint strength of glued laminated timber (glulam) of karamatsu (Larix kaempferi) connected by large finger joint (LFJ) whose finger length was 52mm was estimated using results of tensile and bending strength of LF-jointed laminae. Adequate end-pressure of the LFJ with resorcinol resin adhesive was obtained to be 2 - 5 MPa by the linear portion of relation between load and displacement observed in the inserting compressing test. Using an equation for predicting the modulus of rupture (MOR) for glulam derived by Komatsu, 5th percentile lower limit value of bending strength of glulam connected by LFJ of 120mm width were estimated by observed tensile and bending strength of LF-jointed laminae of 30mm thick and 120mm width. And joint strength of several cross section size glulam connected by LFJ, 120 × 120, 120 × 180 and 120 × 300mm, were obtained by bending test. As a result, observed minimum joint strength on each section size were higher than the estimated MORs. Moreover, good agreement was obtained between estimated MOR curve and estimating strength by size factor for larger cross section size.
