カラマツのLVLを用いた座屈強度の評価手法に関する実験的研究

摘要

In our past study, we conducted compression tests with thick plywood and studied the evaluation method for buckling strength. In this study, we would apply the same method to Laminated Veneer Lumber of Japanese larch. We conducted short-column compression tests and bending tests as a material tests. Then we get yield strain from the short-column compression tests and the yield strain was almost 2400×10~(-6). Next we conducted middle or long-column compression tests with pin-supported on both ends. We could recognize the large bending deformation in those tests. Based on the yiled strain, we got the yield buckling strength(σ_3), get the buckling strength based on southwell method(σ_1)and maximum strength(σ_2). With the ratio(σ_2/σ_3), we could define the limit slenderness ratio and the value was 80 in this study. And finnaly we applied the combination with Euler's and Tetmjer's method as a evalutaion method. As a result, that method is useful to predict the buckling strength for LVL with Japanese larch.%本研究ではカラマツのLVLを用いた座屈強度に関する実験的研究を行った．本研究で得られた知見は以下の点である． 1)短柱の縦圧縮試験と曲げ試験の結果から降伏ひずみを定義しようとする場合，前者の方が小さい値となる傾向が見られた．本試験体における降伏ひずみは，おおよそ2400×10~(-6)であった． 2)細長比を変化させた圧縮試験を行った結果，細長比が大きくなるにつれて耐力が一定となる，いわゆる弾性曲げ座屈となる傾向が見られた．