Static Loading Tests of Glued Laminated Timber Joints with Drift-Pins

摘要

To investigate the effect of modulus of elasticity (MOE) of glued laminated timbers (GLTs) on the mechanical properties of drift-pin joints, we conducted static loading tests of the joints using GLTs with different MOE (5.9, 7.9, 9.8 and 11.8GPa). Species of GLTs were Sugi (Japanese cedar ; Cryptmeria Japonica D. Don) for specimens with 5.9GPa MOE, and Karamatsu (Japanese larch Larix kaempferi Carr.) for other specimens.Two kinds of loading tests were carried out; "Parallel type" in which tensile load was applied parallel to the grain, and "Perpendicular type" in which bending load was applied perpendicular to the grain. Loading pattern was a monotonic for both types.We investigated "five percent offset value" specified in ASTM-D5764, "initial stiffness" calculated by the ratio of a bearing stress to a unit bearing deformation, and "degree of anisotropy" defined as the ratio of the offset value (or the stiffness) of "Parallel type" to that of "Perpendicular type".Positive correlation between the offset value and MOE was observed in "Parallel type", but not in "Perpendicular type". Standard deviation of the offset value and initial stiffness in "Parallel type" were higher than those in "Perpendicular type". The existence of adhesive layers slightly increased the average of the offset value and initial stiffness. The correlation between degree of anisotropy and MOE was weak in both types.