The most comprehensive knowledge of steel structures

First. what is steel structure

What is the steel structure, with the scientific research language, the steel structure should be made of stainless steel plate as the main structure, which is now one of the key structural types of building engineering. Stainless steel plate is characterized by high tensile strength, light net weight, good overall rigidity, and strong deformation ability, so it is particularly suitable for the construction of large-span and very tall and super-heavy buildings. Steel structure is made of steel beams, steel columns, steel tube trusses and other components made of steel grains and carbon steel plates. The structure of each component or component is welded by electric welding, anchor screws or rivets in the middle.

Second. steel structure characteristics

1. stainless steel plate plasticity, good plastic deformation, uniform raw materials, high structural reliability, suitable for destructive driving load, with good building seismic grade characteristics. The internal structure of the stainless steel plate is uniform and tends to a variety of homogenized protoplasm. The specific working characteristics of steel structure are in line with the basic knowledge of calculation. Therefore, the steel structure has high reliability.

2. the raw material tensile strength is high, its net weight is relatively light, the bolt strength is relatively high, the elastic abrasive is also very high. Compared with concrete and wood, the ratio of density and compressive strength is relatively low, so under the same bearing capacity conditions, the steel structure has a small section, and its own weight is light, which is conducive to transportation and installation, suitable for large span, high height, and heavy bearing structure.

3. the steel structure is cost-effective, because the welded structure can ensure complete tightness, can be made of tightness, tightness are particularly good high-pressure vessels, large, small and medium-sized sewage tanks, two types of pressure vessels and so on.

4. steel structure heat resistance is not fire safety, when the temperature is below 150℃, the characteristics of stainless steel plate change not much. Therefore, the steel structure can be used in a thermal production line, but when the surface of the structure is subjected to thermal radiation of about 150 ° C, all aspects of insulation materials should be maintained. The temperature is 300℃ -400℃. Bolt strength and elastic abrasive are significantly reduced, the temperature at 600℃ left, the tensile strength of stainless steel plate tends to zero. In the construction of projects with unique fire safety regulations, the steel structure tries to use fire-resistant insulation materials in all aspects of maintenance to improve the flame retardant level.

5. the corrosion resistance of steel structure is poor, especially in the wet and etched material environment, it is easy to rust. The general steel structure should be rust-proof, hot-dip galvanized or industrial paint, and it should be maintained. For the submarine integrated service platform structure at sea level, it is necessary to adopt special preventive measures such as "zinc block anode protection" to resist corrosion.

6. steel structure production and processing installation automation machinery technology is high, steel structure components are conducive to the production and processing of manufacturers, construction site assembly. The factory's automatic machinery production and processing of finished steel structure components have high precision, high production efficiency, and the construction site assembly speed is quite fast and the construction period is rushed. Steel structure is one of the largest intelligent level of a structure.

Third. the development trend of steel structure history

In the early period of China, there will be unusual casting in iron structure, but because of the bondage of China's feudal society, scientific research does not develop trend, so it has remained at the level of iron buildings for more than 2000 years in China. Until the 19th and 20th centuries, intelligent system steel structure has just begun to be adopted in China. After the establishment of New China, the application of steel structure has a great development trend, regardless of the quantity and quality of far more than to. After 2000, China's social and economic development has been significantly improved, its international status has been significantly enhanced, and China's steel output has become an economic power. Around 2008, under the promotion of the Olympic Games, there has been a boom in steel structure construction projects, strong market demand, promote the rapid development of steel structure construction projects, completed a large number of steel structure exhibition halls, airports, subway and high-rise buildings, among which, some steel structure construction projects in the production and installation of professional with the world's first-class level, Such as the Olympic Bird's Nest stadium and other construction projects. It has achieved a relatively high level in the professional aspects of program design, production processing and installation, and mastered the overall design scheme and construction technology of various complex engineering buildings.

Four. the main characteristics of steel structure

Wind resistance

The steel structure construction project has relatively light net weight, high tensile strength, good overall rigidity and strong deformation ability. The net weight of the engineering building itself is only one-fifth of the brick-concrete structure, and it can withstand 70 meters of hurricanes per second, so that life and property can be effectively maintained daily.

durability

The flat roof of the low-storey villa is mostly slope roof, so the flat roof structure is mostly managed by a triangular portal steel frame system made of cold-drawn steel components. After the light steel structure components are sealed and gypsum board is collected, a very stable "plate rib structure system management" is formed. This structural system manages a stronger building seismic rating and the ability to resist horizontal loads, and can be used in areas with a building seismic rating of more than 9 degrees.

Heat insulation property

The expected effect of sound insulation is a key index to identify the house. The Windows installed in the management of the light steel structure system are all double-layer insulating glass, and the actual effect of sound insulation is particularly good, and the sound insulation is more than 40 sound bars. The wall is composed of light steel keel partition wall and thermal insulation material gypsum board, and the expected sound insulation effect can reach 60 acoustic bars.

Thermal insulation

The thermal insulation material used is glass wool board as the main body, which has good thermal insulation and thermal insulation expected effect. The thermal insulation material used for the wall can scientifically and reasonably avoid the "deformation" of the wall, and achieve the expected effect of heat insulation and insulation. About 100mm thick R15 thermal insulation material thermal resistance value can be equivalent to 1 meter thick wall.

Physical and mental health

Do the construction work, reduce the air pollution caused by waste to the ecological environment, the raw materials of the steel structure of the house can be 100% recycled, and the raw materials of other service facilities can also be mostly recycled, which is in line with the current environmental protection awareness; All raw materials are green energy-saving buildings, taking into account the requirements of ecological environment management, which is conducive to health.

Service performance

The residential structure of light steel structure is all composed of cold drawn thick wall pipe steel component system management, and the draw-anchor is produced and processed by very corrosion resistant and high toughness cold galvanized sheet, which effectively avoids the harm of corrosion of carbon steel plate in the whole process of construction and application, and improves the service life of light steel structure components. The service life of the structure can be 100 years.

Comfort level

The walls of light steel structure are managed with high efficiency, energy saving and environmental protection system, which has respiratory effect and can adjust the dry humidity of indoor air pollution; The roof has the effect of air circulation, which can cause a liquid vapor space above the interior of the house to ensure the air circulation and heat dissipation requirements inside the roof. Five, the advantages and disadvantages of steel structure

Five, the advantages and disadvantages of steel structure

advantage

1. Steel structure residential buildings can be more powerful than ancient Chinese buildings to take into account the relevant provisions of flexible separation of the net width in the construction of the project, and can improve the utilization rate of the floor area according to the reduction of the floor area of the column section and the application of lightweight wall panels, and increase the standard use area in the room by about 6%.

2. the actual effect of energy saving and environmental protection is particularly good, the wall uses light energy saving and environmental protection standardized C-type steel, galvanized square steel, rock wool color steel plate, heat insulation cost-effective, building seismic grade is good. Energy saving and environmental protection 50%,

3. the management of the steel structure system for residential buildings can make full use of the good plasticity of the steel structure, strong plastic deformation ability, with high-quality building seismic grade impact resistance, and further improve the safety and reliability of housing. Especially in the case of natural disasters and super typhoons, steel structures can prevent collapse damage to buildings.

4. the total weight of the construction project, steel structure residential system management itself is light, about half of the concrete structure, can greatly reduce the basic project budget.

5. the construction speed is very fast, the construction period is at least one-third lower than the traditional residential system management, a 1000 square meters only 20 days, five employees can be completed.

6. the actual effect of ecological environmental protection is particularly good. Steel structure residential building construction greatly reduces the amount of sand, stone, ash, the common raw materials are usually green, 100% recycled or melted raw materials, in the engineering disassembly, most of the raw materials can be replaced or melted, not easy to cause waste.

7. Flexible and abundant. Large net width scheme design, the interior space design of the room is suggested to be divided into multiple schemes, and different provisions can be customer-centered.

8. in line with the relevant provisions of building industrialization and international relations. Steel structure suitable factory mass production, high intelligent technology, and can energy saving and environmental protection, waterproof, heat insulation, doors and Windows and other advanced products integrated into one, mechanical equipment application, the program design, production and processing, building construction integration, improve the level of the whole industry chain of infrastructure projects.

defect

1. Diversity

The diversity of engineering quality problems of steel structure engineering projects is mainly manifested in a variety of factors causing commodity quality problems, leading to complex reasons for commodity quality problems, even if it is the same characteristics of commodity quality problems, the reasons are sometimes not the same, so that the analysis, identification and treatment of commodity quality problems improve the diversity. For example, welding gap, which can be generated on the welding stainless steel material, can also be generated in the weld heat damage, both from the welding surface, but also inside the welding; The gap can be welded either vertically or quadrangularly. The gap may be cold or hot. The cause is the improper use of welding materials and improper welding heating or heat after the difference.

2. Ductility

The quality of steel structure construction products will also be accompanied by external changes and the improvement of time and gradually develop towards change, and the quality defects will gradually reflect. For example, the welding of steel components due to changes in the stress field, so that there is no gap in the original welding welding leads to a gap: due to the activity of hydrogen in the welding after welding can lead to a time delay gap. If the member bears the load for a long time, the steel member will cause the lower arch to bend and deformation, causing hidden dangers.

3. Serious harm

The serious harm of steel structure engineering quality problems is mainly reflected in: general, damage to the smooth construction of the building, resulting in delay, cost increase, very serious, construction collapse, resulting in life safety casualties, property damage, resulting in bad social impact.

4. Multiple

Since the modernist design in China is mainly based on concrete structure, construction managers and professional technicians are relatively strangers to the production and construction technology of steel structure, and specific construction personnel with migrant workers as the main body do not understand the scientific research and construction methods of steel structure construction projects, resulting in frequent safety production accidents in the whole process of construction.

Six. the development prospects of steel structure

In China's steel structure industry chain in the past 10 years, the development trend is rapid, has become the global steel structure demand is relatively large, production and processing construction capacity is the strongest, the whole industry chain enterprise scale, enterprise scale of the first steel structure country.

Steel structure enterprises: must attach great importance to the "Twelfth Five-Year" development trend

The successful infrastructure projects of major steel structure construction projects around the country indicate that the comprehensive technical level of steel structure in China has been at a global outstanding level. However, our country's steel structure industry chain also has certain differences with capitalist society in terms of digital management, automated control, standardization, scientific research and technological innovation. 2011 is the beginning of China's "12th Five-Year" master plan, the latest laws and regulations bureau, industry associations and enterprise groups, steel structure enterprises will be in-depth investigation, analysis of market sales and future development direction. The National Development and Reform Commission, the Ministry of Industry and Information Technology of China, and the Ministry of Science and Technology of China have established and overall planned goals for strategic emerging industries related to scientific research, and will be included in the overall plan and give support and support policies for global outstanding levels, strong independent innovation capabilities, strong overall strength of economic globalization and the occupation of the whole industrial chain in many cities. Opportunities are also challenges, in China's steel structure industry chain can ascend the ladder, the scale of operation, the "Twelfth Five-Year" period of development trend is crucial.

In China's steel structure promotion Association experienced research and analysis, after listening to the opinions and suggestions of relevant experts and professors, formulated the "strategic thinking and proposal on the layout of the steel structure industry chain in the government's" 12th Five-Year Plan ", after soliciting the opinions of relevant personnel, the promotion association will organize relevant experts and professors to implement and improve the specific implementation. In order to promote the "Twelfth Five-Year" period of steel structure industry to get a higher development trend.

Steel structure industry due to its economic development of technical advantages, green environmental protection, energy saving and consumption reduction, green development and can be intelligent, industrial development planning development trend, can be more powerful into and determine now in China's social and economic development infrastructure projects must, will also become a spacious market sales, many enterprises, scientific and technological innovation, paved with vitality of one of the new industries.