Structural steel is a category of steel used for making construction materials in a variety of shapes. Most structural steel shapes such as I-beams have high second moments of area which means are very stiff in respect to their cross-sectional area and this can support a high load without excessive sagging.

The erection of structural steelwork consists of the assembly of steel components into a frame on site. The processes involve lifting and placing components into position and then connecting them together. Generally, connection is achieved through bolting, but in some cases site welding is used.