by Lisa Rogers
teel
Lisa Rogers
Copyright 2011 by Lisa Rogers
Introduction
Steel buildings are metal structures made of steel. These metal structures can be used to build offices, hospitals, homes, schools, warehouse and workshops. These steel buildings have gained popularity worldwide. The use of computer aided design technology has given a new dimension to building designs.
Steel has become the leading choice as construction material due to its numerous advantages over other building materials. The steel functions as a skeleton for the building. It performs all the functions a human skeleton does. Steel helps keep the building standing tall. It provides strength to the structure. In addition, steel provides resistance against harsh climatic conditions and gives a sleek appearance to the structure. Maintenance of the steel structure is easier compared to if concrete is used for the same purpose.
Steel buildings can be assembled easily as most of the steel components are pre-engineered. Nuts and bolts can be fixed in the specified holes and the structure can be made in minimum time with less labor. Personalized commercial and industrial buildings can also be made, as steel is now available in different colors and shapes.
1 | Basics of Steel
Steel is an alloy that consists of iron and carbon. Carbon content added to steel depends on the grade of steel and typically ranges from 0.2 to 2.1 %. Carbon is mostly used for alloying with iron but a number of other alloying elements have also been used such as manganese, chromium, vanadium and tungsten.
Carbon and other elements function as hardening agents preventing deformations of iron atom crystal lattice.
The invention of Bessemer process in the mid 19th century improved steel production methods. Further modifications were made in the process to make it cost effective and produce steel of better quality.
Modern processes make steel with different combinations of metal alloys to produce steel with different properties for various purposes.
•Carbon steel is composed of mainly carbon and iron. It makes up 90 % of steel production.
•High Strength low alloy steel (HSLA) has small additions of other elements such as manganese to increase steel strength.
•Low Alloy steel uses alloys of manganese, chromium, nickel or molybdenum to improve the hardness of thick sections.
•Stainless Steel uses 11 % chromium usually combined with nickel to resist rust formation (corrosion).
2 | History of Steel
History of Steel Making
History of steel making goes back to 4th century BC. Steel weapons were produced in Iberian Peninsula. Roman military used Noric Steel (high quality steel from Noricum). Chinese of Han Dynasty created carbon intermediate steel by melting wrought iron together with cast iron.
People of East Africa discovered high heat blast furnace which allowed them to forge carbon steel. This technique was duplicated during Industrial Revolution in Europe.
Evidences of carbon steel production in the Subcontinent was found in Sri Lanka. Unique wind furnace blown by monsoon winds was used to produce high carbon steel. Also known as Wootz steel, it is famous for its durability. Trace elements were also used in production of this steel.
Wootz steel was also produced in India and China. It was a complicated alloy containing Iron as the major component. Steel possessed legendary qualities.
Crucible steel was produced in Merv by slow heating and cooling of pure iron and carbon (typically charcoal) in the 9th -10th century.
History of Steel Buildings
Steel buildings are very popular choice for commercial and residential purposes. They can be used as storage units for business or temporary shelters.
Early 20th century saw a great rise in demand of steel buildings. After World War II, their use became more prevalent. Steel frame shelters were built for the army to provide housing during the War.
After the War army shelters were used as living accommodation. Easy availability of steel then allowed more constructions of steel buildings.
The use of steel buildings became more diverse as the people came to know about the strength and durability of steel.
Prefabricated steel buildings came in to use in 1960. These metal buildings had components premade including roof, floor, frame, walls and bracing. The parts just needed to be put together to make a building stand. This allowed to create buildings in various designs and made construction easier.
First computer aided design steel building was seen in 1960’s. This allowed steel buildings to have more designs, features, shapes and sizes.
Wide varieties of steel buildings are available now including Arch Steel Buildings, Clear span Buildings and Straight walled buildings. The Arch Steel buildings are used as storage units for agricultural business. They are structurally very strong and durable.
Straight walled buildings are less sturdy compared to Arch steel buildings but have more usable space inside.
Clear span buildings use big overhead beams in place of inside support columns. It offers wide open interior spaces to be used for commercial and industrial buildings. It is a great choice for warehouses, factories and storage space. As beams are not included in the structure, you can easily rearrange floor plans according to your needs.
Clear Span buildings are ideal for use as aircraft storage space and maintenance hangers.
3 | Steel in Construction Industry
Using steel as construction material is not only limited to industrial buildings or temporary shelters. Steel has established itself as one of the most versatile construction materials available for use. It has become a popular choice due to its durability, strength and resilience.
Steel is also called as a green product. Concrete and wood cannot be reused, steel can be recycled thus is more cost effective.
Advantages of Using Steel
Steel buildings can be produced and engineered faster than conventional buildings. Pre-engineered steel has cut down the cost and labor. Construction does not require long times. The material can be shipped to the location and joined together to make a strong structure.
Steel buildings are able to withstand the natural disasters. Earthquakes, cyclones, hurricanes, sudden climatic changes can strike anytime. Use of concrete can cause a number of causalities. Also damages caused to the concrete structure need a lot of money to be repaired. Steel is cost effective and resilient.
Termites, rodents and insects cannot house in steel. This will reduce the sufferings of many people who spend loads of money on fumigations.
Steel is lighter but has more tensile strength. It can be used with other construction materials if needed.
Steel structures have more flexibility as compared to other building materials. Components can be shifted from one place to the other without difficulties. You can even add space by extending the structure.
Grades of Steel
Classification of steel in different grades is based on their chemical composition and physical properties. It has been developed by many standard organizations.
•Society of Automotive Engineers (SAE) steel grades.
•British Standards.
•International Organization for Standardization (ISO)
•ASTM International
•Japanese steel grades JIS standard
•Germany steel grades DIN standard
•China steel grades GB standard
Structural Steel
Structural steel is used to produce shapes, structural bars and plates which are used for building and bridge construction. Structural steel has high strength and is flexible.
Structural steel is made from high strength low-alloy (HSLA) steel. HSLA steels are different from other steels in the way that
they are made according to specific mechanical properties not chemical composition.
Typical carbon content of HSLA steel is 0.05-0.25%. Carbon is included for steel to retain its weld ability. Other alloy elements include up to 2 % Manganese and small quantities of copper, nickel, calcium, chromium, vanadium and titanium. These elements are added to strengthen steel and increase resistance to corrosion. Structural steel is formed using heat analysis.
Structural steel shape, composition, size, strength and storage are regulated in most industrialized countries. Steels used for building construction in the US are identified and specified by ASTM International.
4 | Properties of Structural Steel
Following properties of structural steel are considered before using them for a construction. These properties are useful for determining the quality of steel. High quality steel is used so that dependable and long lasting construction is possible.
1.Density
Density of a material is defined as mass per unit volume. Structural steel has density of 7.75 to 8.1 g/cm3.
2.Elastic Modulus
Elastic modulus or modulus of elasticity is the measurement of tendency of an object to be deformed when force or stress is applied to it. Typical values for structural steel
