W-beam steel, whether it's standard or light gauge, due to its relatively high and narrow cross-sectional dimensions, has a significantly different moment of inertia for the two main axes. As a result, it can only be directly used for members that bend within the plane of their web or for forming lattice-type load-bearing components. It is not suitable for members under axial compression or for those with bending perpendicular to the plane of the web, which greatly limits its application range. W-beams are widely used in construction and other metal structures.

Standard I-beams and light I-beams, due to their relatively high and narrow cross-sectional dimensions, have significantly different inertia moments for the two main axes, which greatly limits their application range. The selection of I-beams should be based on the requirements of the design drawings.

In structural design, the selection of I-beams should be based on their mechanical properties, chemical properties, weldability, and structural dimensions, choosing a reasonable I-beam for use.