Deformation capacity demands of structural steel elements

Structural steel design requires the selection of member sizes based on material strength limits obtained from uniaxial tension tests. Traditional design procedures as well as the material properties referenced during these design procedures may not accurately address either the loading conditions or the structural element behaviour. Most structural elements are subjected to a more complex three dimensional stress condition than that of pure uniaxial tension. Material deformation is not only a function of the stress state but is also dependent on anisotropic material properties. The use of the uniaxial tension test in traditional design is compared to the demands made on structural elements due to three dimensional stress states. The anisotropic differences in deformation capacity of structural steels are presented, and related to the deformation demands made on structural steel elements.