Mild steel is a type of steel which is immensely strong. It is a type of steel structure which provides immense strength to buildings. Another important feature of steel framing is its flexibility.
It can actually bend without cracking. Which is why it is a great advantage, as a steel building can flex when it is pushed to one side, either by great wind pressure, or an earthquake.
Another great advantage of steel is its plasticity or ductility. When subjected to great force, it will not suddenly crack like glass, but slowly bend out of shape. This property enables steel building inhabitants to escape as the building bends or deforms.
Steel rarely collapses, therefore a failure in steel frames cannot be sudden. Hence, steel in most cases performs far better in earthquake than most other materials because of these properties.
One weak property of steel is that it quickly loses its strength in fire. Mild steel can lose almost half its strength at 500 degrees Celsius (930 degrees F). There are various methods to address this.
There are several types of steel structures used in constructing buildings. Steel construction is also called steel fabrication.
BOLTED STEEL CONSTRUCTION:
Bolted steel construction occurs when steel fabricators produce finished and painted steel components, which are then shipped to the site and simply bolted in place. The bulk of the fabrication can be done in workshops, with the right machinery, lighting, and work conditions, thus, this is the most preferred method of steel construction.
The size of the components is governed by the size of the truck or trailer they are shipped in.
Once they are shipped to the desired location, the only work to be done at site is lifting the steel structures into place with the help of cranes and then bolting.
This way, the work at site is tremendously fast.
An example of bolted steel construction are pre-engineered buildings, as they are designed, fabricated, shipped, and erected by one company to the owner.
LIGHT GAUGE STEEL CONSTRUCTION:
For residential and small buildings Light Gauge Steel Construction is a type of construction that is common. This is quite similar to wood framed construction, except that light gauge steel members are used in place of wood two-by-fours.
Light gauge steel is steel that is in the form of thin 1-3mm sheets of steel that have been bent into shape to form C-sections or Z-sections.
CONVENTIONAL STEEL FABRICATION:
When teams of steel fabricators cut members of steel to the correct lengths, and then weld them together to make the final structure, this is termed as conventional steel fabrication.
If done at the construction site, it requires a lot of manpower. However, for best results it can be partially done in a workshop to provide better working conditions and reduce time.
Steel structures are super-quick to build at site, and therefore a lot of work can be prefabricated at the factory.
A wide range of ready-made structural sections are available such as, I, C, and angle sections.
Moreover, they can be made to take any kind of shape and clad with any type of material.
Their only drawbacks are that they are susceptible to fire and prone to corrosion in humid and marine environments.
FIRE PROTECTION OF STEEL STRUCTURES
Fire protection is accomplished through a combination of active and passive fire protection methods.
Many steel-framed structures, including some low-rise buildings, sports stadiums, and open-deck parking structures, do not even require fire protection or only require active fire protection (sprinkler systems).
However, when passive fire protection is required, there are several cost-effective coating options that can not only achieve a suitable fire rating, but also look attractive if the steel is left exposed.
The most common way to provide such protection is by spraying low-density fibre or cementitious compounds, now called spray-applied fire-resistive material (SFRM). The product can be sprayed on steel to provide heat resistance and also can be applied over wood, fabric, and other building materials.
CORROSION PREVENTION AND PROTECTION OF STEEL STRUCTURE
Preventing corrosion on structural steel is essential to the overall integrity and aesthetics of the structure. Whether the structural steel supports a bridge, commercial building or plant, asset owners must be able to count on the infrastructure for the long haul. Corrosion is a risk to that infrastructure.
Coatings — the first line of defence — play a major role in protecting structural steel from corrosion. The best-fit coating system is dependent on the corrosiveness of the environment.
STEEL STRUCTURE CONTINUE TO ADVANCE
Advancement in the use of steel in construction industry brought in a new conceptual way of thinking about new but enduring constructional structures.
As steel has higher scale of tensile strength, it allows development of new structural systems (such as cantilevers) and offers unwavering support to build far-reaching aesthetic possibilities (such as gravity-defying skyscrapers) for a construction or related project.
Use of steel is steadily increasing all over the world in construction projects and also in civil engineering related fields. Steel framing is an effective construction method as compared to others. In this article we have discussed the pros and cons of the steel structures