木材の繊維平行方向加力による引張型せん断試験方法の提案

Abstract

High-strength joints used in timber structures are increasing to utilize the shear properties of wood. Thus, it is important to understand the long-term shear performance. Therefore, we proposed the tensile shear testing method to investigate the long-term shear performance of wood. This testing method is to apply stabilized axial load for a long-term and to be able to measure the shear deformation. In order to evaluate the method, the results were compared with results of JIS block shear test. As a result, the mean value of shear strength in the proposed method was 30% lower than the block shear test. The reason for the small results of the proposed method is that the specimen has two shear face and breaks at the weak side, and the shear face is affected by rotation due to the tensile deformation of the perpendicular to grain direction. Therefore, the coefficient of variation of 6.8% in the proposed method shows smaller than 11.1% in the block shear test. And the shear strength value of the proposed method was little bit higher than one of the four-point-bending type shear test methods, and all specimens were shown the shear failure. Based on these results, the proposed method was judged to be useful as a shear test method.