Eight basic knowledge of steel structure
First, the characteristics of steel structure 1. The steel structure has light weight 2. High reliability of steel structure work 3. The steel has good vibration resistance (shock) and impact resistance 4. The degree of industrialization of steel structure manufacturing is relatively high 5. The steel structure can be assembled accurately and quickly 6. It is easy to make a sealed structure 7. Steel structure is easy to corrode 8. Poor fire resistance of steel structure.
Second, grades and properties of commonly used steel structures 1. Carbon structural steel: Q195, Q215, Q235, Q255, Q275, etc. 2. Low alloy high strength structural steel 3. High-quality carbon structural steel and alloy structural steel 4. Special purpose steel.
Third,principles of material selection for steel structures The material selection principle of steel structure is to ensure the bearing capacity of the load-bearing structure and prevent brittle failure under certain conditions. It is comprehensively considered according to the importance of the structure, the load characteristics, the structural form, the stress state, the connection method, the thickness of the steel and the working environment. of. The four steel types proposed in “Code for Design of Steel Structures” GB50017-2003 are the “appropriate” types, and are the first choice when conditions permit. The use of other types is not prohibited, as long as the steel used meets the requirements of the specification.
Fourth, the main technical content of steel structure (1) High-rise steel structure technology. According to the building height and design requirements, the frame, frame support, cylinder and giant frame structure are respectively used, and the components can be steel, stiff reinforced concrete or steel tube concrete. The steel members are light and ductile, and can be welded or rolled steel, which is suitable for super high-rise buildings; stiff reinforced concrete members have high rigidity and good fire resistance, and are suitable for medium and high-rise buildings or bottom structures; steel pipe concrete is easy to construct, For column structures only. (2) Spatial steel structure technology. The space steel structure has the advantages of light weight, high rigidity, beautiful appearance and fast construction speed. The ball joint flat grid, multi-layer variable-section grid and reticulated shell with steel pipe as the rod are the structural types with the largest amount of space steel structure in my country. It has the advantages of large space rigidity and low steel consumption, and can provide complete CAD in the design, construction and inspection procedures. In addition to the grid structure, there are also large-span suspension cable structures and cable-membrane structures in space structures.(3) Light steel structure technology. A new structural form consisting of walls and roof envelopes is made with light colored steel plates. A light steel structure system composed of large-section thin-walled H-shaped steel wall beams and roof purlins welded or rolled by steel plates above 5mm, round steel made of flexible support systems and high-strength bolt connections. 30m or more, the height can reach more than ten meters, and light cranes can be set up. The amount of steel used is 20-30kg/m2. Now there are standardized design procedures and specialized production enterprises, with good product quality, fast installation speed, light weight, low investment, and construction is not limited by seasons, suitable for all kinds of light industrial plants.
Five,objectives and measures of steel structure Steel structure engineering involves a wide range of technical difficulties, and must follow national and industry standards in its promotion and application. Local construction administrative departments should pay attention to the construction of the specialization stage of steel structure engineering, organize the training of quality inspection teams, and summarize work practices and new technology applications in a timely manner. Colleges and universities, design departments and construction enterprises should accelerate the training of steel structure engineering technicians and promote the mature technology of steel structure CAD. The mass academic groups should cooperate with the development of steel structure technology, extensively carry out domestic and foreign academic exchanges and training activities, and actively improve the overall level of steel structure design, production, construction and installation technology, and can be rewarded in the near future.
Six, the connection method of steel structure There are three types of connection methods for steel structures: weld connection, bolt connection and rivet connection. (1) Weld connection The welding seam connection is to partially melt the electrode and the weldment by the heat generated by the arc, and then condense into a weld after cooling, so as to connect the weldment as a whole. (2), bolt connection Bolted connection is to connect the connectors into one body through bolts, such as fasteners. There are two types of bolted connections: ordinary bolted connections and high-strength bolted connections. (3), rivet connection The rivet connection is a rivet with a semi-circular prefabricated head at one end, and the nail rod is quickly inserted into the nail hole of the connecting piece after burning red, and then the other end is riveted into a nail head with a rivet gun to make the connection tight. solid.
Seven, welding connection (1) Welding method The commonly used welding method for steel structures is arc welding, including manual arc welding, automatic or semi-automatic arc welding, and gas shielded welding.(2), the form of the weld The welding seam connection form can be divided into four forms: butt joint, lap joint, T-shaped joint and fillet joint according to the mutual position of the connected components. The welds used for these connections are in two basic forms, butt welds and fillet welds. In the specific application, it should be selected according to the force of the connection, combined with the manufacturing, installation and welding conditions. (3) Weld structure 1. Butt weld Butt welds transmit force directly, smoothly, and have no significant stress concentration, so they have good mechanical performance and are suitable for the connection of components bearing static and dynamic loads. However, due to the high quality requirements of butt welds, the welding gap between weldments is strict, and it is generally used in factory-made connections. 2. Fillet weld The form of fillet welds: fillet welds can be divided into side fillet welds parallel to the force acting direction and front fillet welds perpendicular to the force acting direction and obliquely intersecting the force acting direction according to their length direction and the direction of external force action. slanted fillet welds and surrounding welds.
Eight, bolt connection (1) The structure of ordinary bolt connection 1. The form and specification of ordinary bolts The common form of the steel structure is the large hexagonal head type, and its code is represented by the letter M and the nominal and diameter (mm). M18, M20, M22, M24 are commonly used in engineering.2. Arrangement of ordinary bolted connections The arrangement of bolts should be simple, uniform and compact, to meet the force requirements, and the structure should be reasonable and easy to install. There are two types of arrangement: side-by-side and staggered (as shown in the figure). Parallel is simpler, staggered is more compact.(2) The stress characteristics of ordinary bolted connections 1. Shear bolt connection 2. Tension bolt connection 3. Pull-shear bolt connection (3) The stress characteristics of high-strength bolts High-strength bolted connections can be divided into friction type and pressure type according to design and force requirements. When the frictional connection is subjected to shearing, the maximum frictional resistance that may occur between the plates when the external shear force reaches the limit state; when the relative slip occurs between the plates, it is considered that the connection has failed and is damaged. When the pressure-bearing connection is sheared, the friction force is allowed to be overcome and the relative slip between the plates occurs, and then the external force can continue to increase, and the ultimate failure of the screw shearing or the hole wall bearing pressure is the limit state. https://www.alibaba.com/product-detail/HRC-carbon-steel-coil-industrial-stainless_1600525919171.html?spm=a2747.manage.0.0.623971d2YPOuW6
