Volume 31, Issue 4 (July 2003)
Method of Measuring the Shear Strength of Wood by the Asymmetric Four-Point Bending Test Using a Notched Beam Specimen
We measured the shear strength of wood by the asymmetric four-point bending test using notched beam specimens of Todomatsu (Japanese fir, Abies sachalinensis Fr. Schmidt). The notches were cut on both longitudinal-tangential (LT) planes along the neutral axis, and the load was applied asymmetrically on the longitudinal-radial plane to obtain the shear strength of the LT plane. In the tests, the notch depth and span-to-thickness ratio, which was defined as span/depth ratio, varied and the influence of specimen configuration was examined. Independently of the bending tests, block shear and Iosipescu shear tests were performed and the shear strengths obtained were compared with those obtained by the bending tests. When the specimen had a proper configuration, the value of shear strength was stable over a wide span/depth ratio range and was close to that obtained by the Iosipescu shear test. Hence, we think that the asymmetric four-point bending test using a notched beam specimen is promising for evaluating the realistic shear strength of wood.