Basic knowledge of steel structure

1、 Characteristics of Steel Structures

1. The steel structure has a relatively light self weight

2. High reliability of steel structure work

3. The steel has good vibration (shock) resistance and impact resistance

4. The industrialization level of steel structure manufacturing is relatively high

5. Steel structures can be assembled accurately and quickly

6. Easy to make into a sealed structure

7. Steel structures are prone to corrosion

8. Poor fire resistance of steel structures

2、 The 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

3、 Principles for material selection of steel structures

The principle of material selection for steel structures is to ensure the load-bearing capacity of the load-bearing structure and prevent brittle failure under certain conditions, taking into account factors such as the importance of the structure, load characteristics, structural form, stress state, connection method, steel thickness, and working environment.

The four types of steel models proposed in the "Code for Design of Steel Structures" GB50017-2003 are "suitable" for use, and are the first choice when conditions permit. The use of other models is not prohibited, as long as the steel used meets the requirements of the specification.

4、 Main Steel Structure Technical Content

(1) High rise steel structure technology. According to the building height and design requirements, frames, frame supports, tubes, and mega frame structures can be used, and their components can be made of steel, reinforced concrete, or steel tube concrete. Steel components are lightweight and have good ductility, and can be made of welded, welded, or rolled sections, suitable for ultra high rise buildings; Stiffened reinforced concrete components have high stiffness and good fire resistance, making them suitable for mid to high-rise buildings or bottom structures; Steel tube concrete construction is simple and only used for column structures.

(2) Space steel structure technology. The spatial steel structure has light weight, high stiffness, beautiful appearance, and fast construction speed. Spherical node flat grid structures with steel pipes as members, multi-layer variable cross-section grid structures, and grid shells are the most commonly used structural types of spatial steel structures in China. It has the advantages of high spatial stiffness and low steel consumption, and can provide comprehensive CAD in design, construction, and inspection procedures. In addition to grid structures, spatial structures also include large-span suspension structures, cable membrane structures, etc.

(3) Light steel structure technology. Accompanied by a new structural form consisting of walls and roof enclosure made of lightweight colored steel plates. A lightweight steel structural system consisting of large cross-section thin-walled H-shaped steel wall beams and roof purlins welded, connected or rolled with steel plates of 5mm or more, and flexible support systems made of round steel and connected with high and strong bolts. The column spacing can range from 6m to 9m, the span can reach 30m or more, and the height can reach more than ten meters. It can also be equipped with a lightweight crane. The amount of steel used is 20-30kg/m2. There are now standardized design procedures and specialized production enterprises, with good product quality, fast installation speed, light weight, low investment, and construction without seasonal restrictions, suitable for various light industrial factories.

(4) Steel concrete composite structure technology. Beam and column load-bearing composed of steel or steel management and concrete components