For structural parts, a framework construction using steel profiles and tubes is preferred to a method of construction with concrete, for example, where the following benefits are important: low dead weight of the construction coupled with higher strength, time- and thus cost-saving erection as well as the possibility of making changes subsequently and of disassembling and reassembling it. Constructional steelwork is used on a large scale for bridges, factory buildings, warehouses, transmission towers and skyscrapers (whose skeleton is welded from T-beams). A disadvantage of steel-girder construction is the large effort required for rustproofing. If corrosion resistance, smallest possible dead load or both is of primary concern, aluminium is often chosen - one speaks then of a lightweight construction. Construction based on the properties of aluminium makes use, above all, of profiles (made by extrusion) of alloys containing magnesium and silicon whose strength is near to that of medium-strength structural steels but which are only a third of their weight. They are riveted, welded, adhesively bonded or screwed and at the end of their long utilisation period they can be completely recycled.
- lift, bascule, girder and arched bridges (an arched road bridge 153 metres long with an arch span of 85 metres made from 170 tonnes of aluminium has been spanning the Saguenay River in the province of Quebec, Canada, since 1950)
- multi-storey buildings, workshops, warehouses, roofs of stands, conservatories and greenhouses in the field of building construction
- antenna masts for radio, TV and directional radio equipment and satellite relay stations
- cranes and loading facilities at ports.