It has many applications!
Most steel construction is done with a type of steel called mild steel. Mild steel is a material that is immensely strong. Take a circular bar of steel 1 inch / 25mm in diameter. If you were to attach this bar securely to your ceiling, you could hang from it 20,000 Kg (which is 20 tons), or any one of the following:
- 18 Honda City Cars
- 2 and a half African Elephants
- 1 and a half London City Routemaster Double-Decker Buses
We urge you to try this at home, unless you are married.
This immense strength is of great advantage to buildings. The other important feature of steel framing is its flexibility. It can bend without cracking, which is another great advantage, as a steel building can flex when it is pushed to one side by say, wind, or an earthquake. The third characteristic of steel is its plasticity or ductility. This means that when subjected to great force, it will not suddenly crack like glass, but slowly bend out of shape. This property allows steel buildings to bend out of shape, or deform, thus giving warning to inhabitants to escape. Failure in steel frames is not sudden – a steel structure rarely collapses. Steel in most cases performs far better in earthquakes than most other materials because of these properties.
However one important property of steel is that it quickly loses its strength in a fire. At 500 degrees celsius (930 degrees F), mild steel can lose almost half its strength. This is what happened at the collapse of the World Trade Towers in 2001. Therefore, steel in buildings must be protected from fire or high temperature; this is usually done by wrapping it with boards or spray-on material called fire protection.
WHERE STEEL FRAME STRUCTURES ARE USED
Steel construction is most often used in
- High rise buildings because of its strength, low weight, and speed of construction
- Industrial buildings because of its ability to create large span spaces at low cost
- Warehouse buildings for the same reason
- Residential buildings in a technique called light gauge steel construction
- Temporary Structures as these are quick to set up and remove