Mechanical Properties of Finger-Jointed Wood from Composite Utility Poles Made of Small Diameter Timber

Engineering small diameter timber into structural members may provide an efficient way to utilize low-value material obtained after forest thinning operations. This study evaluates the strength and stiffness properties of finger-jointed and solid wood small clear samples cut from composite poles made of small diameter timber. The strength and stiffness of fi nger-jointed small clear samples were compared with the strength and stiffness of solid wood small clear samples and the strength and stiffness of composite poles. Finger-jointed samples tested in a perpendicular orientation, yielded the lowest bending strength but were not significantly lower than samples tested in a parallel orientation. Therefore, finger joint orientation was not a significant factor regarding the strength of the poles. The bending strength of composite poles was usually lower than the strength of the solid wood samples but higher than the strength of finger-jointed samples cut from the poles. However, the bending stiffness of the composite poles was substantially higher than the bending stiffness of both solid wood and finger-jointed samples cut from the poles.