Properties of Bending, Shearing and Partial Compression of Laminated Lumbers Composed of Sugi and Hinoki Wood with Elements or Laminae of Varying Thickness
Hidekatsu OHNO, Yuusaku KAMEYAMA, Yasuhiro ANDO, Jun TANABE, Futoshi ISHIGURI, Kazuya IIZUKA, Shinso YOKOTA and Nobuo YOSHIZAWA
Abstract:The Strength properties, such as bending, shearing, and partial compression, were examined for full-size specimens（120 by 240 by 4000 mm）of 10-ply laminae of the same thickness（24 mm）of sugi（Cryptomeria japonica）and hinoki（Chamaecyparis obtusa）and 6-ply and 5-ply of hinoki laminae of the same thickness at the outer layer and different thicknesses of sugi elements（36 and 72 mm）.For each piece of laminated lumber, two laminae of hinoki were used on both sides of the outer layer. All strength properties in all types of laminated lumber showed higher values than those of solid sugi lumber. In addition, the coefficients of variation in the modulus of elasticity and modulus of rupture were lower in the laminated lumber than in the solid sugi lumber. On the other hand, no significant differences in strength properties, except for the modulus of shearing, were found among the three types of laminated lumber, suggesting that there was no decrease in strength properties in laminated lumbers made of thick elements instead of laminae. These results indicated that the strength properties of laminated lumbers composed of laminae and elements of different thickness without finger joints were almost the same as those of laminated lumbers composed of laminae of the same thickness. Key Words:Laminated lumber, Bending property, Shearing strength, Partial compression strength