# Connection Methods of Steel Structures
# Connection Methods of Steel Structures There are three connection methods for steel structures: **welded connection**, **bolted connection**, and **riveted connection**. ## 1. Welded Connection Welded connection uses heat generated by an electric arc to locally melt the welding electrode and the workpieces. After cooling and solidifying into a weld seam, the workpieces are integrated into one unit. **Advantages:** - No weakening of the member section, saving steel. - Simple structure and convenient fabrication. - High connection rigidity and good sealing performance. - Easy to realize automatic operation under certain conditions, with high production efficiency. **Disadvantages:** - The heat-affected zone near the weld, caused by high welding temperature, may lead to material embrittlement in some areas. - Uneven heating and cooling during welding result in residual welding stress and deformation, which affect the bearing capacity, rigidity and service performance of the structure. - Due to high rigidity, local cracks can easily propagate to the whole structure, especially brittle fracture at low temperatures. - Relatively poor plasticity and toughness; defects may occur during welding, reducing fatigue strength. ## 2. Bolted Connection Bolted connection uses bolts as fasteners to connect components into one unit. It is divided into **common bolted connection** and **high-strength bolted connection**. **Advantages:** - Simple construction technology and convenient installation, especially suitable for on-site connections. - Easy to disassemble, suitable for detachable structures and temporary connections. **Disadvantages:** - Drilling holes in plates and aligning holes during assembly increase the workload and require high manufacturing accuracy. - Bolt holes reduce the member section. - Connected parts often need lapping or additional connecting plates (or angles), resulting in complicated details and higher steel consumption. ## 3. Riveted Connection Riveted connection adopts rivets with a prefabricated semicircular head at one end. The shank is heated red, inserted quickly into the holes of the connected parts, and then the other end is formed into a head by a rivet gun to achieve a tight connection. **Advantages:** - Reliable force transmission. - Good plasticity and toughness. - Quality is easy to inspect and ensure. - Suitable for heavy structures and structures directly subjected to dynamic loads. **Disadvantages:** - Complicated process, labor-intensive and material-consuming. - High labor intensity. - Therefore, it has been basically replaced by welding and high-strength bolted connections.