Steel structures can be divided into welded structures, bolted structures and riveted structures according to their connection methods. The main connection methods of the current steel structure are welding, bolting and rivet connection.
Further Reading(Steel Structure)
Welding connection is the most important connection method for steel structures at present, also known as welding, which mainly uses high temperature, heating or high pressure to combine metal technology. There are many welding methods, such as hand arc welding, submerged arc welding, tungsten TIG welding, gas metal arc welding, etc. What is actually used depends on the actual needs.
Advantages: simple structure, material saving, easy processing, and automatic operation can be adopted,
Disadvantages: High requirements for materials, welding will cause structural deformation and residual stress in the heat-affected zone, so in the welding process, it should be strengthened to prevent welding deformation defects and correct them in time.
Further Reading: Structural Steel Welding
Bolted connection is also a more common connection method, which is to use bolts to pass through the through-holes of the two parts to be connected, then put washers on, and tighten nuts. This method has the advantages of convenient and rapid assembly and can be used in structural installation connections and detachable structures.
The disadvantage is that the section of the component is weakened and easy to loosen. There are two types of bolted connections: ordinary bolted connections and high-strength bolted connections. The joint bearing capacity of high-strength bolts is higher than that of ordinary bolts, and high-strength bolt connections can reduce the weakening effect of nail holes on components, so they are widely used.
Among them, there are ordinary bolts and high-strength bolts. Ordinary bolts are generally made of ordinary carbon structural steel without heat treatment. High-strength bolts are generally made of high-quality carbon structural steel or alloy structural steel, which needs to be quenched and tempered to improve comprehensive mechanical properties. High strength is divided into 8.8 grades, 10.9 grades, and 12.9 grades. From the strength grade: High-strength bolts are commonly used in two strength grades of 8.8S and 10.9S. Ordinary bolts generally have grades 4.4, 4.8, 5.6 and 8.8. High-strength bolts apply pre-tensioning force and transmit external force by friction, and ordinary bolts transmit shearing force by bolt rod shear resistance and hole wall bearing pressure.
Ordinary bolt connection
Advantages: easy loading and unloading, simple equipment
Disadvantages: When the bolt accuracy is low, it is not suitable for inspection. When the bolt accuracy is high, the processing and installation are complicated and the price is high.
High strength bolt connection
Advantages: Friction type has small shear deformation and good elastic performance, especially suitable for structures with follow-up load. The bearing capacity of the pressure-bearing type is higher than that of the friction type, and the connection is compact
Disadvantages: The friction surface is treated, the installation process is slightly complicated, and the cost is slightly higher; the shear deformation of the pressure-bearing connection is large, and it should not be used in structures that bear dynamic loads.
learn more about Types Of Connections In Steel Structures
A non-removable static connection that uses rivets to connect two or more components (usually plates or profiles) together, referred to as riveting. Rivet connection has the characteristics of simple technology, reliable connection and non-removable type.
The rivets are generally classified as follows:
Hot driven rivets: The rivets which are driven in the hot conditions
Shop rivets: The rivets which are placed in the workshop
Field rivets: The rivets which are placed in the site/field.
Cold-driven rivets: Since high pressure is required to form the head at room temperature this type of rivet is limited.
Advantages: Reliable force transmission, good toughness and plasticity, easy quality inspection, good resistance to dynamic loads
Disadvantages: complex structure, expensive steel and labor
Although there are three connection methods for steel structure engineering, welding is the main method in the production process of structural parts. The quality of welded products is related to the quality of products used in the overall building. Therefore, welding must be fully welded, must not miss welding.