Erection of structural steel work consists of the assembly of steel components into a frame on site,he processes involve lifting and placing components into position, then connecting them together - generally using bolting but sometimes using site welding. The assembled frame needs to be aligned before bolting up is completed. Often the ability to complete these processes safely, quickly and economically is influenced significantly by early decisions made during design long before erection commences. It is important that designers clearly understand the impact that their decisions can have; "build ability" is a valid design objective.