Shear Strength of Structural Composite Lumber Using Torsion Tests
Gupta, R
Dept. of Wood Science and Engineering, Oregon State University, Corvallis, OR

Siller, T
Dept. of Wood Science and Engineering, Oregon State University, Corvallis, OR

(Received 20 October 2003; accepted 16 September 2004)

Abstract
Torsion tests were used to determine the shear strength of full-size structural composite lumber (SCL). Eighty-five rectangular specimens of laminated strand lumber (LSL), laminated veneer lumber (LVL), and parallel strand lumber (PSL) were tested. LSL failed along the strand (LT Plane) and in a brittle manner. LVL and PSL failed across the veneer/strand (LR plane) and in a ductile manner. Different failure modes were observed due to the differences in the shear moduli in two longitudinal planes (G_LT and G_LR). Based on orthotropic theory, the shear strength of LSL, LVL, and PSL is 6.43 MPa (t_LR), 7.96 MPa (t_LT), and 6.82 MPa (t_LT), respectively. Based on the results of this study, the torsion test is recommended as a standard method for determining the pure shear strength of full-size SCL, since it is the only known test method to date that imposes a state of pure shear stress in the specimens.

Keywords:
full-size tests, mechanical properties of wood, shear properties, shear strength, timber engineering, torsion tests, wood mechanics, wood science and technology

Paper ID: JTE12287
DOI: 10.1520/JTE12287

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Author Gupta, R Affiliation Dept. of Wood Science and Engineering, Oregon State University, Corvallis, OR Author Siller, T Affiliation Dept. of Wood Science and Engineering, Oregon State University, Corvallis, OR Author Gupta R, Siller T Title Shear Strength of Structural Composite Lumber Using Torsion Tests Symposium , Committee on