Steel is a mixer from alloy which consists a lot of iron and around 0.2 % of carbon. Grade will affect the weight of it but normally it is 2.1% by weight. For iron, carbon is the most common alloying material, but it also uses other elements such as manganese, chromium, vanadium, and tungsten. Carbon and other alloying elements likes what I mentioned just now are acting as a hardening agent. From doing so, it can prevent dislocations in the iron atom crystal lattice from sliding past one another. By control the amount of alloying elements, it can indirectly control the hardness, ductility and the tensile strength of the resulting steel. By increasing the carbon content, it can be made harder and stronger than iron, but such steel is also less ductile than iron. Steel also called as a versatile material because the composition and internal structure to tailor its properties can be adjusted by us. Due to this reason, we can produce steel for paperclips, steel bridges, thin strips of steel for razor blades and large beam for column.
Properties of steel
Steel more or less is a linear elastic material, it has a strong tensile strength which made it can be bend into whatever shape that you like, and it also have the same compressive as the tensile strength . It different from concrete, as we know that concrete is very low in tensile strength but it has a strong compressive strength. However, with enough applied force, steel and other metals will cease to behave elastically and begin to behave plastically. When a material is linearly elastic, its deformation, or strain, will be directly proportional to the applied force and it will return to its original shape when the force is removed. A plastic material ,on the other hand, will permanently deform without breaking.
In real life, we can't found such thing as perfectly elastic or plastic material. Material likes steel, the tensile strength and the compressive strength are concerned by structural engineers. When steel reaches its yield strength, It started to stretch and transition from elastic to plastic behavior. When there is more force that applied on steel, it will made it reaches its ultimate tensile strength and eventually it will break. Due to the high tensile strength that steel has, structural engineers take this advantage in their design. In some Natural disasters likes earthquake or major structural failure, the properties which steel has is very useful because it allows the structure to absorb extra load. For those material that too brittle, it will shatter instead of stretch, it possibly will cause the structure to crash down, but for material likes steel, when the structure is ruined, but its plastic behavior allows time for escape.
Advantage of steel
As all engineers know, steel is very useful in construction. There are a lot of advantages of using steel in construction. That is why so many construction in the world use steel as main material.
Use steel in construction only will generate a small amount of waste. For all those light gauge steel construction is 100 percent recyclable. In one year, over a trillion pound of steel was recycled. According from a trustable data, it shows steel industry annually saves energy up to 18 million households for a year.
2. Strong and Durability
Compare with use wood for framing work, steel is significantly stronger than wood. Other than carbon fiber, there is no other material can match steel's superior strength and durability. The reason we never apply carbon fiber in our building is because carbon fiber is much more expensive compare with steel. Building that uses steel will enable the building to resist earthquake, hurricanes and other natural disease.
3. Climate and Condition
As we know, steel made from strong iron and carbon, so it will never crack, shrink, splinter, creep, split, or swell. Individual members of a wood-framed building react differently to climate changes. This wood movement may include expansion, contraction, warping, twisting, etc.
Steel's weigh is 60 percent lesser than wood. 6 tons of steel can supports 2000 square foot home, but for lumber, it needs around 20 tons to support 2000 Sf home.
Although steel is light but it is very strong. Use steel for foundations can make it be lighter; transportation and site handling are easier.
Problem of steel
There is no perfect material in this world; each material has their strong point and week point. For steel, the most serious problem is corrosion. Due to the moisture of the air, those steel that exposed to air will get rush easily. Owner of the house have to spend a lot of money to remove those rush steel and replace it with new steel. So rather than waste a lot of money to replace after it rush, engineer had found out some way to prevent it before get rush.
1. Materials resistant to Corrosion
In real life, we can't find a material that can totally immune to corrosion in all environments. To prevent corrosion, we have to know the environment factor that causes them to rush. Corrosion Resistance Date are used to assess the suitability of material in an environment.
2. Protective coating
For prevent steel from corrosion, protective coatings are the most widely used technique. Protective coatings separate the surfaces of the matter that will corrode from the factors in the environment which cause corrosion to occur. Even protective coating is a common way of corrosion control technique, but it doesn't mean it can 100 percent the surface.
3. Catholic Protection
There is another way to prevent corrosion from using electricity. Catholic protection interferes with the natural action of the electrochemical cells that are responsible for corrosion. For those materials which always exposed to air or water, using Catholic protection method is a very good technique.
Other than the corrosion problem, steel can't resist heat as well. So when in applied in column, it needs a thick layer of cement to resist fire. From doing this, when the building is in fire, people got a lot of time to run from the building before it collapse.
Uses of steel in construction work
The number of building keeps increasing nowadays with help of steel components all over the world. The engineer found out that steel that is very useful in the construction work due to the ability of tensile and compressive strength. Cost of steel also affordable by client. In a building, steel parts are the most strong, most solid and reliable type of all building material that can stand the test of time.
Due to the reason which is steels are firm, and cheaper compare with other material, aesthetic, fire resist, do not require further treatment and it is environmentally friendly. Advantage of steel is enough to draw attention to metal and steel components; the only issue that needs even more elaboration is their elasticity and reliability. Nowadays people do not want to be scared anymore because of their firbeboard-house or pvc houses will be sweep away by storm, tornados and other natural disasters. Reliable, solid and firm components will brings trust to user.
Corrosion is one of the biggest disadvantages of metal parts used for construction though nowadays most of the manufacturers heat-treat metal parts in order they become stainless and stone-like. Heat conductivity is another problem of metal structures that is why houses are not equipped with them in full scale.
The method of securing the ends of a column greatly influences its strength. While wooden and cast-iron columns usually occur in building construction with flat or square ends, structural-steel columns are often used, having either hinged, flat or square, and fixed ends. Where the ends are securely fixed, so that the column is likely to fail in the shaft, before the end connections are ruptured, greater strength is developed than with columns having hinged or pinned ends. Columns having flat or square ends are somewhat stronger than hinged-end columns, but not so strong as those having their ends firmly secured.
Light steel framing
Thin sheets of galvanized steel can be formed into steel studs used as a building material for rough-framing in commercial or residential construction (pictured), and many other applications. The dimension of the room is established with horizontal track that is anchored to the floor and ceiling to outline each room. The vertical studs are arranged in the tracks, usually spaced 16" apart, and fastened at the top and bottom.
Rectangular steel frame, or "perimeter frame" of the Willis building (at right) contrasted against the diagrid frame at 30 St Mary Axe, London, UK.
The primary shapes used in residential construction are the C-shape stud and the U-shaped track, and a variety of other shapes. Framing members are generally produced in a thickness of 12 to 25 gauge. The wall finish is anchored to the two flange sides of the stud, which varies from 1-1/4" to 3" thick, and the width of web ranges from 1-5/8" to 14". Rectangular sections are removed from the web to provide access for electrical wiring.
Steel mills produce galvanized sheet steel, the base material for light-gauge steel. Sheet steel is then roll-formed into the final profiles used for framing. The sheets are zinc coated (galvanized) to prevent oxidation and corrosion. Steel framing provides excellent design flexibility due to the inherent strength of steel, which allows it to span over a longer distance than wood, and also resist wind and earthquake loads.
Light Steel Framing has been extensively used in cold climate countries due to its good thermal and structural behaviour. Heat loss reduction and tenement thermal comfort have been the main driving forces defining the design of these frames. The main issue to be addressed is how striving for thermal efficiency can lead to structural weakening and poor fire performance.
Steel is a very important character in construction work. It can apply in concrete, farming work, beam, column, etc. Steel strong in tensile and compressive, so when apply in column, it can help column to easily crack or damage. Compare with wood make building, steel make building allow people run away from the building when it was in fire.
Steel can be totally recycled, and it will not produce any waste when it apply in construction. Talk about the advantage, steel is strong and it can last longer than any material. Carbon fiber has same properties as steel, but cost of carbon fiber is extremely expensive compare with steel.
There is no perfect material in the world, even steel is good, but it can corrode anytime when I expose to air or water. Client or owner spent a lot of money for the further treatment. So rather to spend money on the further treatment, they choose to do something on it before it install. Such way like coating, material resist, and catholic protection.
Initially I choose wood as the material of the assignment, but eventually I found out that steel is more common use and it's properties is very unique. Steel much more stronger than wood, lighter than wood and talk about the further treatment, woods are easily spoil, so it will waste more money. But nowadays steels are getting lesser, we have to find another material to replace it, Carbon fiber has the same properties with steel but the problem is it is very expensive compare with steel. Recycle is the best way to solve this problem. Steel can be cycle easily, we can get the source from tin, old car, old building's beam. From doing this, we can make sure