Introduction to steel construction

Example

Compared with brick and concrete structure, steel structure building has obvious advantages in environmental protection, energy saving, high efficiency, factory production and so on. The 325m-high Diwang Tower in Shenzhen, the 421m-high Jinmao Tower in Pudong, Shanghai, the Beijing-Guangzhou Center, Bird's Nest, CCTV New Building, Water Cube and other large buildings in Beijing have all adopted steel structure. Beijing, Shanghai, Shandong, Liaoning, Inner Mongolia and other provinces and cities have started to carry out steel structure residential pilot projects, among which, Beijing Jinchen Apartment has been listed as the demonstration project of housing steel structure system by the Ministry of Construction. It is expected that the 21st century will be the century of metal structure and steel structure will become the backbone of the new architectural era. Humans began to use pig iron in the 1670s and wrought iron in the early 19th century to build Bridges and houses. Steel structures have a longer history of development than reinforced concrete structures, and their vitality is becoming stronger and stronger. In the United States, more than 70 percent of the market for low-rise buildings, such as non-residential buildings below two stories, is already made up of construction metal. Among the 101 super high-rise buildings that have been completed in the world, 16 have reinforced concrete structure, 59 have pure steel structure, and 27 have different forms of steel-concrete mixed structure. It can be seen that the development of steel structure will promote the construction industry, metallurgy industry, machinery industry, automobile industry, agriculture, petroleum industry, commerce, transportation industry to develop rapidly.

The largest steel structure Plant Museum in Asia -- On January 23, 2013, the Plant Museum of Qingdao International Horticultural Exhibition in Qingdao, China, was capped with a leaf shape. Plant Museum project is located in Baiguoshan Forest Park, north of Tianshui Road, covering an area of 2.44 hectares, with a total construction area of 22,749 square meters, including 13,522 square meters of above-ground construction and 9,227 square meters of underground construction, which is one of the largest steel structure plant museum in Asia, with a total cost of 293 million yuan [2].

Because of its leaf shape, a total of 3,000 tons of steel structure, more than 14,000 pieces of assembled rods, the total length of weld more than 17,000 meters, more than 15,000 pieces of special glass, so the construction is difficult, the process is extremely strict. The task of on-site splicing and welding of the structure is particularly heavy and the lifting difficulty is particularly great. The total length of the weld of the steel structure spliced on site alone is more than 17,000 meters, which is equivalent to the welding amount of 10,000 tons of conventional steel structure engineering.

Advantage

The "bulk weight to strength ratio" of steel is generally less than wood, concrete and masonry, so steel structure is relatively light, compared with reinforced concrete structure to 30% to 50% light; In addition, steel structure section is small, compared with reinforced concrete structure can increase the effective area of the building about 8%. At the beginning of 20th century, steel structure was adopted in Songhua River steel girder bridge, Yellow River Bridge, Shanghai International Hotel, etc.; After the establishment of New China, the development speed of China's civil high-rise steel structure is further accelerated, and Beijing has taken six of the ten high-rise steel structure buildings in the country. Beijing-guangzhou Center (208 meters high), Beijing Mansion (182 meters high), International Trade Tower (155.2 meters high), Changfu Palace Hotel (90.9 meters high), Shangri-La Hotel (82.7 meters high), the Industrial and Commercial Bank of China (48.3 meters high), and the National Grand Theater project under construction. Hundreds of airports across the country will be designed with steel structures to speed up construction and increase space. Thus, the economy of high speed development needs steel structure.

Basic condition

Policy and technical conditions are in place. At the beginning of the year, the Ministry of Construction and the State Administration of Metallurgical Industry jointly organized the Technical Coordination Group of Steel for construction to formulate the "Tenth Five-Year Plan and 2015 Development Plan Outline for the National Construction Steel Structure Industry". The outline clearly states: Steel structure has a series of advantages such as high strength, light weight, good seismic performance, fast construction speed, provincial foundation cost, small footprint, high degree of industrialization, beautiful appearance, in addition, steel structure building also has a good sense of space, can be designed into a large number of open offices around the sky garden, central patio and reasonable elevator design can achieve the lowest energy consumption. So the steel structure is environmental protection and energy - saving building structure. Compared with concrete structure, it is environmentally friendly, reusable and easy to industrialization structure. Steel structure is widely used in housing construction in developed countries. Financial Street is the most modern block in Beijing. In view of the above advantages of steel structure housing, as the only high-grade apartment in Financial Street, Jin Chen Apartment has been designed into a high-grade steel structure housing in order to create a more comfortable sense of space and save energy. It has been rated as the first residential steel structure system demonstration project of the Ministry of Construction in Beijing after the announcement of the outline. It is also the only small high-rise steel structure residential project in Beijing.

Foundation

The increase of steel products and construction steel has laid a good foundation for the development of steel structure. With the steel production breaking through 100 million tons in 1996, China has become a major iron and steel power in the world. As the country focuses on the future development of metallurgical science and technology, it is expected that by 2020, China will become a powerful iron and steel power in the world. In the past, the H section steel which could not be produced for a long time can now be produced in "Maanshan Iron and Steel", "Laigang" and Anshan No.1 Rolling Mill. The maximum section of H-section steel has reached 700mm, with an annual capacity of 1.4 million tons. The annual production capacity of color steel plate for light steel structure has reached 700-900,000 tons, and the annual production capacity of cold-formed steel is about 1.2 million tons. This laid the foundation for the development of steel construction. The development goal of building steel structure during the "Tenth Five-Year Plan" period is to strive to achieve the annual construction steel structure steel accounted for 3% of the country's total steel production. The development goal of building steel structure in 2015 is to strive for the annual steel volume of the national building steel structure to reach 6% of the total steel. Thus, our country construction steel structure development will go on a new level. Efficient welding process and application of new welding and cutting equipment. For example, all kinds of reverse liner methods of double-sided forming single wire and multi-wire submerged arc welding, longmen I beam double side double wire fast welding production line, a variety of CNC flame machine and laser cutting machine, for steel structure efficient production and production of high quality products to create a good condition. The use of high-efficiency welding materials, such as gas shielded welding and self-contained flux cored wire and various high-efficiency electrodes, will account for about 40% of total welding material production by 2005; The friction type strong bolt and the automatic torque control method as well as the development of new technology and new materials such as anticorrosion and fire prevention have created good conditions for further development of steel structure engineering.

Development mode

Energy saving, high efficiency, environmental protection and industrialization. In the last few years of the 20th century, Chinese urban housing construction with annual completion area of 440 million square meters, the total output value of 600 billion yuan (about 9% of GDP), the housing industry has become a new growth point in the new century of the national economy. To realize the modernization of housing industry and solve the problems in housing construction, such as low level of industrialization, low rate of parts, low grade of housing materials, low life span, high energy consumption of solid clay brick and unfavorable to environmental protection, has been listed as an urgent problem to be solved in the new century. The Chinese construction industry requires the whole industry to study the new system of steel structure in all kinds of buildings, expand its application scope and develop multi-storey steel structure buildings. Internationally, American designers and structural engineers attach great importance to the study of metal structure and its durability, practicability and economy. European experts put forward that steel structure has the conditions of green building, that is, conducive to environmental protection and energy saving buildings. They believe that metal structure buildings have a good sense of space, can achieve innovative planning and space design, architecture, not only living, use, more should consider to create more comfortable space for people, energy saving space. Japan produced 59 million tons of steel in 1998, and the steel used in building structure accounted for 13 percent. In addition, steel structure residential buildings accounted for a considerable proportion of the steel used in building structure. In Hong Kong, high-rise buildings are everywhere. Taiwan earthquake, it is obvious that steel structure building is better than reinforced concrete building; According to the earthquake damage, the general multi-story house basically collapsed to the ground, while the steel structure of the house did not collapse, so the Taiwan authorities required that the multi-story house construction must be made of steel structure. The pilot of steel structure in multi-storey residential buildings and small high-rise residential buildings was started in Tianjin. Tianjin adopted three different structures, different wall materials, different construction methods. Pilot projects covering more than 200,000 square meters will be launched. One is to adopt square concrete-filled steel tube column with large space structure; The second is steel truss structure; Third, concrete filled steel tube structure is adopted. The square meter steel of the three structures is less than that of the reinforced concrete structure. Qingdao, Shanghai and Xinjiang have listed a certain area of housing projects for pilot. Because our country "steel residential building" just starts, many structures can't be mass-produced, therefore, steel structure would be more expensive than concrete structure. According to the calculation of the construction unit of Beijing Jinchen Apartment, although the price of steel structure is relatively high on the whole, the comprehensive cost is not high because of the short construction period, low energy consumption, high utilization rate and improved quality. Meanwhile, because this is the first steel structure residential demonstration project in Beijing, the suppliers all provide steel structure parts at the most favorable price. The total cost is about the same as the concrete structure.