Abstract
Many experimental reports on the influence of notch and its dimensions upon the strength and stiffness of wooden beam have been reported in the world. By refering to these test results, the following equations (1) and (2) calculating the extreme fiber stress in bending (σ) are provided for notched beam in "A.I.J. Structural Standards". For a beam having a notch on its compression side at or near the cross section subjected to maximum bending moment (M_max) : σ=M_max/Z_n…(1) in which Z_n is a net value of section modulus at the notched cross section. For the beam having a notch on its tension side at or near the cross section subjected to maximum bending moment (M_max) : σ=M_max/0.6Z_n…(2) in which Z_n is a net value of section modulus at the notched cross section whose notching shoould be less than one-third the depth of the cross section without notch. The first aim of our experimental project was checking whether equation (2) is applicable or not for the notched cross section where notching is more than one-third the depth of the portion without notch. The second aim was the examination of applicability of equations (1) and (2) for the laminated wooden beam in which the bottom of notch is just coincident the glue line between laminae. The tests were made on the ordinary and the laminated wooden beams. The cross section was 6cm(width)×12cm(depth) and a notch was cut on the compression or the tension sides. And the ratio of the notched depth to the non-notched depth was diveded into three kinds : 1/2, 1/3 and 1/6.
