Study on the Effect of Finger-Joints on the Strengths of Laminations from Fiber-Managed Eucalyptus nitens

Abstract

The performance characteristics of finger-joints as a jointing technique for Eucalyptus nitens is crucial for their use in engineered wood products. This research evaluated the strength of the finger-jointed laminations made from fiber-managed E. nitens. A total of 237 specimens with (117 pieces) and without (120 pieces) finger-joints were sectioned from finger-jointed laminations and tested by bending, tensile, shear, and bearing tests. Bending and tensile tests were paired to identify any correlations. The mean value with finger-joints for bending and tensile were 92.1 MPa and 79.6 MPa, respectively. The presence of finger-joints reduced the strength values. Joint efficiencies in bending and tensile are 0.73 and 0.62, respectively. The distributions of bending and tensile strength were similar for the samples without finger-joints. For the samples with finger-joints, tensile strength was significantly lower than paired bending strength. Shear test results show that the short-span test is inefficient in obtaining the shear strength of fiber-managed E. nitens boards. Meanwhile, the finger-joint efficiency in the bearing is 0.86. The prediction models of lamination’s bending, tensile, and bearing strength were established by non-destructive properties as predictors. Bending strength was highly correlated to the modulus of elasticity value, while tensile and bearing strength were correlated to density. This study obtained promising results on finger-jointed boards from fiber-managed E. nitens suggesting they could be suitable for structural purposes.