Estimating the structural capacity of skin-timber

In Korea, the market for wood products used in construction has been growing rapidly. Public opinion polls show that for wooden structures, Koreans prefer post-and-beam type construction with structural timber and exposed structural members because of its good appearance. Skin timber is expected to have good drying properties, improved efficiency of chemical injection, and good dimensional stability. To learn about the mechanical properties of skin timbers, we prepared various miniature skin timber specimens for pine and larch. Bored skin timber samples with five different boring diameters and non-bored sample specimens were used to determine their mechanical strength loss as a factor of the boring diameter. We found a relationship between strength characteristics and boring diameter that was highly significant statistically in the case of pine but not highly significant in the case of larch which has large variation in strength performances among groups. We developed a number of types of estimating equations for pine and larch, but a linear function was selected as the estimating equation for residual strength versus boring diameter because of its convenience. The coefficient of determination and regression equation were 0.97, y=-1.7664x+49.046 for pine and those values for larch were 0.87, y=2.4285x+68.599, respectively.