2007 IUFRO Division 5 Conference Taipei

5.02.00 Physiomechanical properties of wood and wood-based materials and their application

Chih-Lung Cho

Department of Natural Resources National I-Lan University

Forest Product and Environment: A Productive SymbiosisForest Product and Environment: A Productive Symbiosis

Mechanic Properties of Structural Lumber Produced from Thinned Wood of Japanese Cedar Grown in Taiwan

Chih-Lung Cho*, Li Chwen Lin, Jiunn Haur Chen, Huey Lan Wang

National I-Lan University

Department of Natural Resources

No. 1, Sec. 1, Shen-Lung Rd.

260, I-Lan

Taiwan, R.O.C

Department of Natural Resources National I-Lan University

Forest Product and Environment: A Productive SymbiosisForest Product and Environment: A Productive Symbiosis

Department of Natural Resources National I-Lan University

Aim of study and methods

In order to understand the mechanic properties and lumber grade of structural lumber produced from thinned log of Japanese cedar grown in Taiwan by using:

Visual grading and mechanical stress grading

Edgewise transversal vibration and bending test methods for measuring stiffness and MOR of lumber

Department of Natural Resources National I-Lan University

Results

Mechanical properties of visual and mechanical stress grade lumber

Visual grades

Density

(kg/m3)MOE(GP

a)MOR(MPa)

Allowable bending stress(MPa)

Construction 444 9.03 49.51 15.57

Standard 442 7.81 44.00 12.17

Utility 448 7.78 42.88 12.13

Below grade 448 8.31 42.83 10.73

Mechanical stress grade

Ebe (GPa)Allowable bending stre

ss (MPa)

E5 4-6 11.65

E7 6-8 14.26

E9 8-10 17.23

E11 10-12 20.57

E13 12-14 22.08

Department of Natural Resources National I-Lan University

Conclusions

Vibration technique is suitable used for on-line mechanical stress grading operation system.

Establishment of allowable bending stress of Japanese cedar could make more efficient use of the available timber resource in meeting timber structure requirements.