Knowledge of steel structure

First. what is steel structure

What is steel structure, with scientific research language to speak steel structure to stainless steel plate production as the main body of the structure, 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, strong deformation ability, so it is particularly suitable for the construction of large span and very tall, 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. Each component or component in the middle of the electric welding, anchor screws or rivets connected structure.

Two. steel structure characteristics

1. stainless steel plate plasticity, plastic deformation is good, uniform raw materials, high structural reliability, suitable to bear the destructive driving force load, with good building seismic grade characteristics. Stainless steel plate internal structure uniform structure, tend to a variety of homogeneous protoplasm. The concrete working characteristics of steel structure accord with the basic knowledge of calculation. Therefore, the steel structure has high reliability.

2. raw material tensile strength is high, its net weight is relatively light, bolt strength is relatively high, elastic abrasive is also very high. Compared with concrete and wood, the proportion of density and compressive strength is relatively low, so in the same bearing capacity of the steel structure member section is small, its weight is light, conducive to transportation and installation, suitable span, high height, heavy bearing structure.

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

4. steel structure heat resistance is not fire safety, when the temperature is below 150℃, stainless steel plate characteristics do not change much. Therefore, the steel structure can be used in hot production line, but when the surface of the structure is subjected to thermal radiation of about 150℃, all aspects of the maintenance of thermal insulation materials should be used. The temperature is between 300℃ and 400℃. Bolt strength and elastic abrasive are significantly reduced, the temperature at 600℃ left, stainless steel plate tensile strength tends to zero. In the construction project with unique fire safety regulations, the steel structure as far as possible 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. General steel structure to rust, hot dip galvanized or industrial paint, and to maintenance. For the structure of the submarine integrated service platform at sea level, it is necessary to adopt special preventive measures such as "zinc block anode protection" to prevent corrosion.

6. steel structure production, processing and installation of automation machinery technology is high, steel structure components are conducive to the production and processing of manufacturers, construction site assembly. Factory automatic mechanical production and processing of steel structure components of high precision, high production efficiency, construction site assembly speed is quite fast, catch up with the construction period. 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 would be unusual casting in the aspect of iron structure, but because of the restriction of China's feudal society, scientific research did not develop trend, so the level of iron buildings in China has been permanent for more than 2000 years. It was not until the 19th and 20th centuries that intelligent system steel structure was just adopted in China. After the establishment of New China, the application of steel structure has a great development trend, no matter in quantity and quality far exceed to. After 2000, China's social and economic development was significantly improved, and its international status was significantly enhanced. China's steel output became an economic power. Around 2008, driven by the Olympic Games, there has been a boom in steel structure construction projects. Strong market demand has promoted the rapid development of steel structure construction projects, and a large number of steel structure exhibitions, airports, subway and high-rise buildings have been completed. Among them, some steel structure construction projects have the world's first-class level in the professional production and installation. Such as the Olympic Bird's Nest stadium and other construction projects. In the program design, production processing and installation and other professional aspects have done a relatively high level, master a variety of complex engineering building overall design scheme and construction technology.

Four. the main characteristics of steel structure

Wind resistance

The net weight of section steel structure is relatively light, the tensile strength is high, the overall rigidity is good, the deformation ability is strong. The net weight of the engineering building itself is only one-fifth of the brick and concrete structure structure, can withstand 70 meters per second hurricane, 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 mostly adopts the triangular portal steel frame system management made of cold-drawn steel members. The light steel structural members form a very stable "plate rib structural system management" after sealing the structural plate and collecting gypsum board. This structural system has a stronger building seismic rating and the ability to resist horizontal load, can be used for building seismic rating of 9 degrees or more area.

Heat insulation

The expected effect of sound insulation is a key index to evaluate the housing. The Windows installed in the management of light steel structure system are all double-layer insulating glass. 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 gypsum board, the expected sound insulation effect can reach 60 sound bars.

Thermal insulation

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

Physical and mental health

Do construction work to 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 most recycled, which is in line with the current awareness of environmental protection. All raw materials are green and energy saving buildings, taking into account the requirements of ecological environment governance, which is conducive to health.

Service performance

The residential structure of light steel structure is composed of cold-drawn thick-wall tube steel member system management, and the draw-anchor is produced and processed with very corrosion resistance and high toughness cold-tied 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 structural members. The service life of the structure can be 100 years.

Comfort level

Light steel structure wall adopts high efficiency, energy saving and environmental protection system management, with respiratory effect, can adjust indoor air pollution dry humidity; The roof has the effect of air circulation, which can make the indoor air flow between the steam bodies, to ensure the internal air circulation and heat dissipation of the roof. 5. Advantages and disadvantages of steel structure.

Five. Advantages and disadvantages of steel structure

Advantage

1. steel structure residential building than the ancient Chinese architecture can be more powerful considering the relevant provisions of flexible separation in the construction of the project, and can reduce the area of the column section and the application of light wall panel, improve the utilization rate of the area, the room standard use area increased by about 6%.

2. The actual effect of energy saving and environmental protection is particularly good. The walls are made of light energy saving and environmental protection standardized C-type steel, galvanized square steel, rock wool color steel plate. Energy saving and environmental protection 50%,

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

4. the total weight of the construction project, steel structure housing 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 housing system management, a 1000 square meters only 20 days, five employees can complete.

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

7. flexible, rich. Large width scheme design, room interior space design suggestions of multiple scheme segmentation, can be customer-centered different provisions.

8. In line with the relevant regulations of building industrialization and current international relations. Steel structure suitable for mass production by manufacturers, high intelligent technology, and can integrate energy saving and environmental protection, waterproof, heat insulation, doors and Windows and other advanced products into one, mechanical equipment application, the program design, production and processing, 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 the various factors that cause the quality problems of commodities, and the reasons for the quality problems of commodities are complex. Even if the quality problems of commodities with the same characteristics, the reasons are sometimes not the same, so that the analysis, discrimination and treatment of the quality problems of commodities improve the diversity. For example, welding gap, which can be produced on the welding stainless steel material, can also be produced in the weld thermal damage, both from the welding surface, but also in the welding inside; The gap can be welded vertically or quadrilateral in space. The gap may be cold or hot. The cause is the improper use of welding materials and welding heating or after heat improper difference.

2. Ductility

Steel structure construction commodity quality problems will be accompanied by changes in the outside world and the improvement of time and gradually develop trends change, quality defects gradually reflected. For example, due to the change of stress field in the welding of steel components, the electric welding without gap leads to gap: because of the activity of hydrogen in the welding after welding, the gap can be delayed by time. If the component is a permanent load, the steel component will cause the lower arch to bend and deform, causing hidden dangers.

3. Serious harm

The serious harm of steel structure engineering quality problems is mainly reflected in the following aspects: in general, it will harm the smooth construction of the building, causing time delay and cost increase; in very serious cases, the collapse of the engineering building will cause life safety casualties, property damage and bad social impact.

4. Multiple

Because in China modernist design to the concrete structure as the main body, construction managers and professional technology engaged in the production and construction technology of steel structure is relatively stranger, the specific construction personnel with migrant workers as the main body do not understand the construction methods of steel structure construction projects, resulting in the whole process of construction safety accidents often caused.