The small steel buildings tend to be prefabricated or simple enough to be constructed by anyone.
Prefabrication offers the benefits of being less costly than traditional methods and is more environmentally friendly (since no waste is produced on-site). The larger steel buildings require skilled construction workers, such as ironworkers, to ensure proper and safe assembly.
Advantages steel buildings:
- Steel provides several advantages over other building materials, such as wood:
- Steel is structurally sound and manufactured to strict specifications and tolerances.
- Any excess material is 100% recyclable.
- Steel does not easily warp, buckle, twist or bend, and is therefore easy to modify and offers design flexibility. Steel is also easy to install.
- Steel is cost effective and rarely fluctuates in price.
- Steel allows for improved quality of construction and less maintenance, while offering improved safety and resistance.
With the propagation of mold and mildew in residential buildings, using steel minimizes these infestations. Mold needs moist, porous material to grow. Steel studs do not have those problems.
History
The use of steel for structural purposes was initially slow. The Bessemer process in 1855 made steel production more efficient, and cheap steels, which had high tensile and compressive strengths plus good ductility were available from about 1870, but wrought and cast iron continued to satisfy most of the demand for iron-based building products, due mainly to problems of producing steel from alkaline ores. These problems, caused principally by the presence of phosphorus, were solved by Sidney Gilchrist Thomas in 1879.
It was not until 1880 that an era of construction based on reliable mild steel began. By that date the quality of steels being produced had become reasonably consistent.
The Home Insurance Building, completed in 1885, was the first to use skeleton frame construction, relying on its masonry cladding for stability. In this case the iron columns are merely embedded in the walls, and their load carrying capacity appears to be secondary to the capacity of the masonry, particularly for wind loads. In the United States, the first steel framed building was the Rand McNally Building in Chicago, erected in 1890.
The Royal Insurance Building in Liverpool designed by James Francis Doyle in 1895 (erected 1896-1903) was the first to use a steel frame in the United Kingdom.
The rolled steel "profile" or cross section of steel columns takes the shape of the letter "I". The two wide flanges of a column are thicker and wider than the flanges on a beam, to better withstand compressive stress in the structure. Square and round tubular sections of steel can also be used, often filled with concrete. Steel beams are connected to the columns with bolts and threaded fasteners, and historically connected by rivets. The central "web" of the steel I-beams is often wider than a column web to resist the higher bending moments that occur in beams.
Wide sheets of steel deck can be used to cover the top of the steel frame as a "form" or corrugated mold, below a thick layer of concrete and steel reinforcing bars. Another popular alternative is a floor of precast concrete flooring units with some form of concrete topping. Often in office buildings, the final floor surface is provided by some form of raised flooring system with the void between the walking surface and the structural floor being used for cables and air handling ducts.
The frame needs to be protected from fire because steel softens at high temperature and this can cause the building to partially collapse. In the case of the columns this is usually done by encasing it in some form of fire resistant structure such as masonry, concrete or plasterboard. The beams may be cased in concrete, plasterboard or sprayed with a coating to insulate it from the heat of the fire or it can be protected by a fire-resistant ceiling construction. Asbestos was a popular material for fireproofing steel structures up until the early 1970s, before the health risks of asbestos fibres were fully understood.
The exterior "skin" of the building is anchored to the frame using a variety of construction techniques and following a huge variety of architectural styles. Bricks, stone, reinforced concrete, architectural glass, sheet metal and simply paint have been used to cover the frame to protect the steel from the weather.