We are living in an age that is dominated by the marvels of technology. In the past century itself, architecture has evolved from short stone and wood structures to massive towers of metal. Today, the Burj Khalifa in Dubai is a staggering 830 meters tall! That’s almost a kilometer of steel into the sky! A very useful compound, steel was used earlier in the manufacture of daily use items. It is only recently that man has discovered its value when it comes to buildings. Over the years, these have gotten better and better.
Steel is considered a “green” product in that it is entirely recyclable. In fact, the builder will be able to buy recycled steel for a new commercial building or home. In our new project ‘Winds OF Change’ at Akkulam we built our club in an acre with steel structure. All around the world there are buildings that soar to record heights, bridges that span the widest rivers, and sculptures that unite nations. And yet, we sometimes forget that many of the world’s iconic structures, like Chicago’s Willis Tower, the Shun Hing Square Tower,the Taipei 101 Tower,the Burj Khalifa,The Sydney Harbour would not have been possible without steel.
Steel structures is a very important subject for undergraduate civil engineers. Steel is an alloy of carbon and iron. It used in construction and other applications because of its Hardness and tensile strength. Due to the tensile strength of steel, it is added in concrete otherwise concrete is very much powerful in compression. Many of the structures in the whole world are made of steel. Steel has many advantages and disadvantages depending upon them one can adopt the choice of steel structures. There are many shapes available in steel structures like angle iron, channels, W sections, I sections, Z sections, circular, hollow and many others. In modern construction, steel structures is used for almost every type of structure including heavy industrial building, high-rise building, equipment support system, infrastructure, bridge, tower, airport terminal, heavy industrial plant, pipe rack, etc.
Steel frame is typically consisting of vertical column and horizontal beams which are riveted, bolted or welded together in a rectilinear grid. Steel beams are horizontal structural members that resist loads applied laterally to their axis. Columns are vertical structural members that transfer compressive loads. It can be used to form the skeleton of a building.
1.Light-Gauge Metal Buildings
Light gauge steel construction is very similar to wood framed construction in principle – the wooden framing members are replaced with thin steel sections. The steel sections used here are called cold formed sections, meaning that the sections are formed, or given shape at room temperature. This is in contrast to thicker hot rolled sections, that are shaped while the steel is molten hot. Cold formed steel is shaped by guiding thin sheets of steel through a series of rollers, each roller changing the shape very slightly, with the net result of converting a flat sheet of steel into a C or S-shaped section.
2. Bolted Steel Construction
In this technique, all structural steel members are fabricated and painted off-site, then delivered to the construction site, and finally bolted in place.The size of the steel structural members is controlled by the size of the truck or trailer used to deliver steel elements. Commonly, the maximum length of 6m m is acceptable for normal truck and 12m for long trailer.Bolted steel construction is substantially fast because lifting the steel members into place and bolting are all the works that need to be executed on construction site.
It is considered to be the most preferred construction approach because the most of the fabrication can be done in workshops, with the right machinery, lighting, and work conditions.
3. Conventional Steel Fabrication
Conventional steel fabrication involves cutting steel members to the correct length and welding them to build the final structure.This construction process may be executed on site entirely which require massive manpower.Alternatively, for best results it can be done in a workshop partially to provide better working conditions and reduce work-time.
The steel used here is coated with zinc (called galvanized) or a mixture of zinc and aluminum (called zincalume or galvalume by some) to protect it from corrosion. The thickness of this coating can be varied to suit a range of environments. Typically, marine environments require the most protection, and dry, arid regions the least.
Advantages of Steel Frame Construction
Steel frame constructions offer the following advantages compared to brick, concrete and wooden constructions.
- Strength & Durability
Structural steel components are lighter and stronger than weight-bearing wood or concrete products. A typical weight-bearing steel fabrication is 30% to 50% lighter than a wooden equivalent. This makes steel frame construction far stronger and more durable than traditional wood framed alternatives.
- Environment friendly
Steel can be easily recycled at the end of its lifespan. This means you won’t have to spend millions of dollars in disposing of non-recyclable construction waste. Steel buildings are energy efficient in comparison to other building materials.
- Easy Fabrication In Different Sizes
Steel studs are available in a variety of sizes and can be fabricated order. This means they can be customized to bear specific loads in buildings of all different types and sizes.
- Fire Resistance
Steel frame constructions are highly resistant to fire, reducing the fire risk to a building and retarding the spread of a fire should one occur. Special flame retardant coatings act to increase this property of structural steel.
- Pest & Insect Resistant
Structural steel components are immune to the degrading effects of burrowing insects and mammals – which can cause a problem for wooden framework unless adequately treated.
- Moisture & Weather Resistance
Structural steel can have good moisture resistant properties, depending on its carbon content. Hot zinc coating and extra powder treatments for enhanced rust resistance will make a structural steel component even more immune to the effects of water – an important consideration for components exposed to the weather.
- Easy to install
The steel frames are properly fabricated to fit correctly with one end skidding into the other. Also, it does not require huge manpower in construction sites. This speeds up the building time and enables completion of large-scale projects in just a few weeks. A faster construction timeline also reduces the labour costs.
- Safe and resistant
Steel frame buildings are more blaze resistant than any other building material. Also, steel remains unaffected by bugs, termites, and rodents. It does not need to be treated with chemicals. Additionally, steel frame buildings are well grounded and thus, are less probable to be hit or impaired by lightning. They are also resistant to fire and can stand natural calamities like earthquakes.
- Design flexibility
Steel framing motivates home designers to think out of the box and make the most of the available space. It can be shaped perfectly into non-conventional roof lines and innovative designs. This feature of steel helps create unique, individualised homes. Plus, the high strength-to-weight ratio of steel roof framing allows column-free open spaces.
- Earthquake resistance
Earthquakes are unpredictable in terms of magnitude, frequency, duration, and location. Steel is the material of choice for design because it is inherently ductile and flexible. It flexes under extreme loads rather than crushing or crumbling. Many of the beam-to-column connections in a steel building are designed principally to support gravity loads. Yet they also have a considerable capacity to resist lateral loads caused by wind and earthquakes.