WOOD

One of the oldest construction materials is wood which, technically speaking, belongs to the group of polymer matrix composites; one which is conveniently and expertly produced by Nature. Due to its organic cell-type structure, the density of wood remains modest. Thus, as its strength and stiffness can - in certain cases - attain remarkable values, its levels of specific strength and stiffness (absolute strength or stiffness divided by density) can reach magnitudes which are competitive with those of other construction materials. It is demonstrated, for instance, that the specific strength of wood in the axial direction can exceed those of low-carbon steel and concrete. Its specific stiffness can also be comparable to those of aluminum alloys and low-carbon steels, and is better than that of concrete. In constructional design, especially in the dimensioning of supports, the values of specific strength and stiffness are of utmost importance.