What is steel construction？
Steel construction, as the name implies, is a building construction constructed with architectural steel as the main structure and load-bearing structure. Such buildings usually consist of beams, columns, trusses, and other components made of section steel and steel plates to form a load-bearing structure. Then, the load-bearing structure and the building’s roof, floor and wall, and other enclosure structures together form the overall building construction.
Construction section steel usually refers to hot-rolled angle steel, channel steel, I-beam, H-beam, and steel pipe. A building whose components constitute a load-bearing structure is called a “section steel structure building”. And, the load-bearing structural building formed by cold-rolled, crimped or uncrimped thin-walled L-shaped, U-shaped, Z-shaped, and tube-shaped steel plates, as well as their components made of small steels such as angle steel, bars, etc., is generally called “light steel building”. In addition, there are buildings with suspension cables using steel cables, which are also steel structures.
Compared with traditional concrete buildings, steel structure buildings use steel plates or section steel instead of reinforced concrete, which has higher strength and better seismic resistance. And because the components can be manufactured in factories and installed on-site, the construction period can be greatly reduced. At the same time, because steel can be reused, construction waste can be greatly reduced, making it more environmentally friendly.
It is precisely because of these advantages of steel structure buildings that are widely used in industrial and civil buildings all over the world. In modern buildings, steel structures are used for almost all types of structures, including heavy industrial buildings, high-rise buildings, equipment support systems, infrastructure, bridges, towers, airport terminals, heavy industrial plants, pipe racks, etc.
At present, the application of steel structure buildings in high-rise and super high-rise buildings is becoming more and more mature. And it has gradually become the mainstream construction technology, which is the development direction of future buildings.
The brief history of steel construction
1660 Hooke discovered the proportional relationship between material deformation and force (Hooke’s law).
1744 Euler deduced the stability limit load formula of the stalk, which is still used today.
1779 The first cast iron arch bridge, Coalbrookdale Bridge in England was completed.
1786 France built the French Theater in Paris with an iron + glass roof.
1820 Philadelphia built the first cast-iron building.
1828 Vienna built the first steel bridge.
1851 The “Crystal Palace” exhibition hall designed by London gardener Paxton was a glass and iron frame structure, which fully expressed the mechanical instinct of industrial production. “Crystal Palace” ushered in a new era of architectural forms.
1856 U.S. began to produce steel.
1874 Eads Bridge, the first large-span steel truss bridge, was built in St. Louis.
1881 Arc welding process came out.
1883 Brooklyn Suspension Bridge was completed. It was built in 1869
1889 The “Eiffel Tower” and “Machinery Pavilion” were designed at the French World Expo. The “Eiffel Tower” is an elevated iron structure with a tower height of 328M. The “Machine Pavilion” is an unprecedented large-span structure, setting a new world architectural record, with a length of 420M and a span of 115M. The structural method uses the principle of a three-hinged arch for the first time.
1889 CHICAGO’s The Rand Mcnally Building was completed, becoming the first all-steel building with 10 floors.
1890 The Firth of Forth Bridge in Scotland was completed, using 55,000 tons of steel and 57 lives. 8 million rivets were shipped home.
1907 The United States established Bethlehem Steel (Bethlehem Steel).
1908 Bethlehem Steel began to produce hot-rolled steel.
1909 Peter of the German Manufacturing Alliance. Behrens designed the “Berlin General Electric Turbine Workshop”, which is characterized by a steel structure and large glass windows. It is known as the first truly modern building.
1909 Massachusetts used hot-rolled steel for building structures.
1914 Kazinczy, Hungary, proved that the beam has a plastic hinge limit behavior.
1921 American Institute of Steel Construction AISC was established
1923 AISC issued the first edition of the steel structure design code AISC-ASD (allowable stress method).
1930 Weathering steel came out.
The Empire State Building in New York was completed in 1931, with 102 floors and a height of 381 meters.
1944 Column Research Council (CRC) was established.
1940 Lehigh University began to study the ultimate strength of structures and components.
1947 High-strength bolt specification published.
1950 Northeast China formulated internal regulations for steel structure design.
1953 The world’s first suspended cable roof was built, the Leyley Stadium in North Carolina, USA, the beginning of modern cable structure.
1954 China promulgated the first “Code for Design of Steel Structures” (Regulation 4-54) Allowable Stress Design Method.
1955 The Soviet Union issued the НйТУ 121-55 specification. Japan’s Nakanoshima Steel Works began to produce lightweight steel.
1956 China adopted the НйТУ 121-55 standard issued by the Soviet Union as the reference standard.
1957 The plastic design method was applied to architecture for the first time.
1960 Japan’s SEKISUI HOUSE company launched the A-shaped steel structure residence.
1961 Beijing Workers’ Gymnasium was built. The beginning of China’s modern suspension cable structure.
1962 Japan’s Yamato Corporation launched A-type steel structure residences.
1964 China’s second “Code for Design of Steel Structures” was promulgated.
1965 Japan’s Matsushita Housing launched R2N steel structure housing.
1970 The World Trade Tower, the tallest building in the world, was built, 410 meters high.
1973 The Sears Tower, the tallest Chicago Sears Tower at the time, was completed, with 110 floors and a height of 442 meters.
1974 China issued TJ 17-44.
1976 Wind tunnel laboratory research at the University of Western Ontario in Canada. This research has contributed to the wind load regulations of MBMA, SBC, and some other countries in the world, and is widely used in low-rise metal structure systems.
In the same year, French USINOR developed refractory steel that can withstand 900℃.
1980 Japanese steel pipe company NKK developed OLAC steel plate technology (TMCP steel plate).
1983 AISC issued the first AISC-LRFD, the limit design method.
1988 China promulgated the “Code for Design of Steel Structures” (GBJ 17-88) Probability Limit Design Method.
1994 Japan published JIS G3106 SN steel standard.
1995 The Hanshin Earthquake demonstrates the seismic performance of steel structures.
1996 China became the world’s largest steel producer. The steel output is over 100 million tons.
2009 Burj Khalifa was completed.
Which steel is used in steel construction？
Carbon steel is an iron-carbon alloy with a carbon content of less than 2% and small amounts of silicon, manganese, and impurities such as phosphorus and sulfur. The carbon steel used in industrial applications generally has a carbon content of no more than 1.4%. Carbon steel is the earliest and largest basic material used in modern industry. Carbon steel according to its quality can be divided into ordinary carbon structural steel and quality carbon structural steel two categories. High-quality carbon structural steel provisions of sulfur, phosphorus content is lower than the allowable ordinary carbon steel, so the integrated mechanical properties than ordinary carbon steel.
Manufacturing methods: Carbon steel smelting is usually carried out in the converter, flat furnace. The converter generally smelts ordinary carbon steel, while the flat furnace can smelt a variety of high-quality steel. In recent years, oxygen blowing converter steelmaking technology has developed rapidly. And there is a trend to replace the flat furnace steelmaking. The liquid steel will be injected into the ingot mold, you get a variety of steel ingots. After forging or rolling, the ingots are processed into various shapes of steel and forgings. After pressure processing, the ingot is able to improve the internal organization of the steel and the distribution of inclusions, so the same composition of steel is superior to the ingot performance.
It is mainly used to make machine parts and various metal components that do not require high strength. It is not only widely used in construction, bridges, railways, vehicles, ships, and all kinds of machinery manufacturing industry, but also in the modern petrochemical industry, marine development, etc. It is one of the most widely used and versatile steel. It is one of the most widely used and most versatile steel.
Alloy steel refers to the steel made by adding other elements (such as chromium, nickel, molybdenum, vanadium, titanium, copper, tungsten, aluminum, cobalt, niobium, zirconium, and other elements) in addition to iron and carbon. An iron-carbon alloy formed by adding an appropriate amount of one or more alloying elements on the basis of ordinary carbon steel. According to the different added elements and adopting appropriate processing technology, special properties such as high strength, high toughness, wear resistance, corrosion resistance, low-temperature resistance, high-temperature resistance, and non-magnetic properties can be obtained. According to the content of alloying elements in steel, it can be divided into low alloy steel, medium alloy steel, and high alloy steel.
The alloy steel commonly used in steel structure buildings is low-alloy high-strength structural steel, which is made by adding a small amount of alloying elements on the basis of carbon structural steel (Wc=0.16%~0.2%). This kind of steel has good welding performance, plasticity, toughness, and processing technology, better corrosion resistance, higher strength and lower critical transition temperature of cold brittleness. Low-alloy high-strength structural steel is suitable for manufacturing large-scale steel structures such as buildings, bridges, ships, vehicles, railways, and large-scale military engineering.
Rebar is a kind of steel bar, which is a kind of building material. For example, in reinforced concrete, it is used to support the framework of the structure.
There are mainly two types of steel bars, hot-rolled and cold-rolled, and the most common steel bars are hot-rolled steel bars. Hot-rolled steel bars are finished steel bars that are heated, rolled, and cooled naturally. Such as hot-rolled ribbed steel bars, hot-rolled round steel bars. Cold-rolled steel bars are steel bars that are cold processed and formed on the basis of hot-rolled steel bars (mainly hot-rolled round wire rods). Such as cold-rolled ribbed steel bars, steel strands, etc. According to the rolling shape of the hot-rolled steel bar, it can be divided into two categories: smooth steel bar and ribbed steel bar.
In actual use, steel bars are often divided into 4 grades according to their strength grades. Among them, Grade I, Grade II, and Grade III hot-rolled steel bars are often used in non-prestressed reinforced concrete. Grade IV steel bars are often used in prestressed reinforced concrete because of their high strength and lower plastic deformation capacity than Grade I～III steel bars. . In addition, using grade II and grade III steel bars as the force-bearing steel bars of reinforced concrete structures can save 40-50% of steel than using grade I steel bars. Therefore, it is widely used in large and medium-sized reinforced concrete structures such as bridges, dams, port projects, and houses. The main reinforcement of the building structure.
Structural steel refers to steel that meets a specific level of strength and formability. It is formed of precise cross-sections and follows clear mechanical properties and chemical composition standards. This steel is very strong and durable, with good ductility, high strength, and good durability. In actual use, it can be changed into almost any shape according to different needs, such as I-shaped steel, Z-shaped, HSS-shaped, L-shaped (angle steel), structural channel steel (C-shaped steel, cross-section), T-shaped, rail profile, Bars, Rods, Plates, web steel open trusses, etc.
Structural steel has reliable fire performance, and with corresponding fire protection, it can effectively extend the time for fire rescue. For designers, the ductility of structural steel provides a high degree of customization. Structural steel has high strength and durability and can withstand wear and tear in many kinds of weather. At the same time, with the improvement of anti-corrosion measures, the service life of structural steel can last for decades. After the structural steel is produced in the factory, it can be constructed almost immediately when it arrives at the construction site. This not only saves time but also makes the environment safer, making it a popular choice for green enterprises.
Currently, structural steel is used in a wide range of industrial and residential applications, including high-rise buildings and skyscrapers, as well as garages and large agricultural buildings.
Light Gauge Steel
Light gauge steel is a type of cold-formed steel that is manufactured by adding elements to make coils of varying thicknesses and then, using a machine, bending and forming the long, thin sheet through a series of rollers into a strong “C” or “Z” form that can withstand heavy loads.
Light gauge steel can be divided into two systems: the Australian system and the American-Japanese system. The Australian system uses 0.75MM-1.15MM galvanized steel, which has the following advantages: thinner thickness and cross-section, better cross-sectional corrosion resistance, and cost savings due to reduced steel consumption. The American-Japanese system uses 0.8MM-1.2MM galvanized steel, which has the general advantage of higher overall steel consumption, a relative reduction in strength, compliance with the overall design of the load, and a thicker steel plate.
Because light gauge steel uses machines for precise processing, cutting and sizing are almost unnecessary at the worksite. Also, due to the lightweight of light gauge steel, transportation and installation are very convenient. And the construction speed is fast. Light gauge steel can realize the long-span design and high degree of customization. As a lightweight metal, it will not decay, split, warp, shrink, twist, burn, or become termite food.
Light gauge steel is young and very vital steel that has been widely used in general construction sites, agriculture, commerce, and service buildings, such as office buildings, warehouses, stadiums, entertainment, tourist buildings, and low- and multi-story residential buildings.
What are the advantages of steel construction?
Regarding the advantages of steel structure, we can get a clearer understanding from the comparison between it and concrete structure and wood structure.
- Steel has a high strength/weight ratio. As a result, the weight of the steel structure is relatively small. This function makes steel an attractive structural material for high-rise buildings, long-span bridges, and regional buildings with low soil bearing capacity and high seismic activity.
- Steel undergoes large plastic deformation before failure, so it provides a large reserve force.
- Predictable material properties. The properties of steel can be highly determined. In fact, steel generally exhibits high elasticity under well-defined stress levels. Compared with reinforced concrete, the properties of steel will not change much over time.
- Installation speed. Steel components only need to be installed on the structure, so the construction time is very short. Usually, this can bring faster economic returns in areas such as labor costs.
- Easy to repair. Generally speaking, steel structures can be repaired quickly and easily, which can effectively save related material and labor costs.
- Modification of prefabs. Steel is very suitable for prefabrication and mass production. After the designer has designed the structure, it can be uniformly produced in a specialized factory.
- The recovery rate of steel is very high, and it can be reused after dismantling the structure. It is a relatively green material.
- Expand the existing structure. The steel structure can be easily extended by adding new frames or wings. This feature makes the steel bridge may be widened.
- Fatigue strength. The steel structure has relatively good fatigue strength.
- Long-term storage. After the cement reacts with water and the mixture hardens, the concrete cannot be stored once it is mixed. Its main components must be stored separately.
- Curing time. Concrete has a 30-day curing period. This factor has a great influence on the construction progress of the building. This makes the installation speed of cast-in-situ concrete slower than steel. However, the use of precast concrete can be greatly improved.
- Higher cost. The cost of casting reinforced concrete is relatively high.
- Larger cross-section. For multi-story buildings, the reinforced concrete column section (roller compacted concrete) in the case of RCC is larger than the steel section due to its lower compressive strength.
- Shrinkage leads to crack development and strength loss.
- The shrinkage and expansion of wood are one of its main disadvantages. Wood is a hygroscopic material. This means it will absorb the condensable steam around it and lose moisture to the air below the fiber saturation point.
- Another disadvantage is its deterioration. The factors that cause wood deterioration and destruction are divided into two categories: biological (biological) and non-biological (non-biological). Biological agents include rot and mold, bacteria, and insects. Non-biological agents include sunlight, wind, water, certain chemicals, and fire.
- Land use permit. Regardless of any country in the world, the first step in building a house is the review of land use rights to ensure the legality of house construction.
- Contact the supplier and design the drawings. Investigate the surrounding environment, topography, and other factors, and communicate with customers to determine the preliminary design plan. Then, the supplier will finalize the design drawings, communicate with customers, and even finalize the draft.
- After the drawings are finalized, the steel structure building can be built, and the factory will arrange the production. The whole production process is carried out on an industrialized assembly line. All parts will be produced and cut according to the strict specifications listed in the approved license drawings, ensuring the unity of the steel structure and the quality of each part.
- Ground and site preparation. This step is critical and must be performed correctly to ensure successful construction and stable structure. Ground and site preparations will be carried out before the arrival of the building. This includes pouring the foundation slab and setting up the foundation bolts of the building itself. Make sure to use a reputable contractor to ensure that the slab is flat and the anchor bolts are properly secured.
- Transportation and installation. The processed steel structure will be transported to the construction site for erection, installation, and final decoration. This “production-erection” construction mode greatly shortens the construction period, increases the construction period and labor costs; in addition, it also reduces the construction waste on the construction site, which is in line with the social pursuit of modern life, energy conservation, and environmental protection.
- Acceptance and delivery. After construction, it will enter the final acceptance link. The relevant quality supervision department will start the construction acceptance of the steel structure house and finally, start the delivery phase.
The Market for Steel Construction
Regarding the market scale of steel structure buildings, we can have a glimpse from the market data of structural steel, the main material of steel structure buildings.
In 2019, the global structural steel market is worth 100.3 billion U.S. dollars, and it is estimated that from 2020 to 2027, the annual growth rate can reach 5.6%.
Due to the increasing demand for high-quality building materials in the industry, commerce, offices, and public buildings, the non-residential sector is expected to achieve significant growth. In many non-residential applications, structural steel is widely used, including healthcare facilities, data centers, large retail stores, stadiums, airports, and manufacturing facilities.
In some developed countries, construction steel can account for more than 50% of total steel consumption, steel structure steel can account for more than 30% of steel output, and steel structure area can account for more than 40% of the total construction area.
According to data reports, steel frame houses in Australia and Japan account for 50% of the number of houses, and steel frame houses in the United States account for about 20% of the total number of houses. Finland, Sweden, Denmark, and France have all formed large-scale industrial steel structure houses. system.
It can be estimated that in the next 30 years, the rapid population growth and the acceleration of urbanization in developing countries will provide a broad development space for the civilian housing market, while traditional buildings have low production efficiency and severe damage to the environment and cultivated land. Economic development has brought a great burden. Therefore, in the new round of housing construction, energy-saving and land-saving green and environmentally-friendly steel structure housing will face new development opportunities.
Wrapping it up
With the development of the construction industry, the application of steel structure buildings is becoming more and more common. Compared with traditional concrete buildings, steel structure buildings have replaced reinforced concrete with steel plates or section steels, which have higher strength and better seismic resistance. And because the components can be manufactured in factories and installed on-site, the construction period is greatly reduced. Because the steel can be reused, construction waste can be greatly reduced, and it is more environmentally friendly.
With the development of the global economy and the construction industry, the application of steel structures has become more and more extensive. Steel structure projects are developing from industrial buildings with large spans, multi-story or high-rise buildings, and high heat resistance requirements to civil buildings. Steel structure buildings will inevitably have a very broad space, and may even become the mainstream in the future building system.