Durability of timber and laminated timber and the effects of environmental conditions on its mechanical properties

Massive wood is an orthotropic material due to its internal structure. In other words, the physical and mechanical properties of wood show variance in lengthwise, radial and tangential direction. Dimensional change in wood, swelling with moisture and shrinkage due to heat shows difference in three directions. Wood shows dimensional change mostly in the tangential direction, less in the radial direction and least in the longitudional direction . Therefore, the resistance and elasticity modules also change in three directions. In addition, different kinds of wood also show differences in dimensional change due to their different cell types. Properties of wood such as its specific weight, proportion of summer wood, grain direction, grain angle, and knots also affect its durability properties. In this study it was decided to carry out further studies on the material and experimental and theoretically, the durability of the massive and laminated spruce woods against the ambient conditions was investigated and the effect of these conditions on the mechanical properties was revealed.