In the field of modern construction, steel structures are widely used in industrial and civil buildings and general structures due to their advantages such as high strength, light weight and short construction period. In order to ensure that steel structures are safe, reliable, economical and technologically advanced throughout their life cycle, steel structure design specifications came into being. The steel structure design specification adopts the limit state design method based on probability theory (except fatigue calculation) and performs accurate calculations through the partial factor design expression. When designing, it is necessary to fully consider the consequences of structural damage and reasonably determine the safety level. For general industrial and civil building steel structures, the safety level is mostly level 2. The design of load-bearing structures must take into account the ultimate state of bearing capacity and the limit state of normal use. The ultimate state of bearing capacity covers strength damage of components and connections, fatigue damage, excessive deformation leading to inability to bear loads, instability of structures and components, transformation of structures into mobile systems, and overturning of structures; the limit state of normal use includes deformation that affects the normal use or appearance of structures, components and non-structural components, vibration that affects normal use, and local damage that affects normal use or durability (such as concrete cracks). In terms of material selection, it is necessary to select appropriate steel grades and materials based on factors such as structural importance, load characteristics, connection methods, and working temperature. For example, load-bearing structural steels are mostly open-hearth or oxygen converter No. 3 steel, 16Mn steel, etc., and different situations have detailed requirements for steel performance assurance. Connection materials such as welding rods, welding wires, bolts, etc. should also be compatible with the strength of the main metal. When calculating, the load design value is used for strength, stability, and connection strength calculations; the load standard value is used for fatigue calculations and deformation calculations under normal use limit states. For structures that directly bear dynamic loads, the dynamic load design value needs to be multiplied by the dynamic coefficient when calculating strength and stability, while the dynamic load standard value is not multiplied when calculating fatigue and deformation. The steel structure design specification provides unified standards and guidance for the industry. Only by strictly following the specifications can steel structures continue to play their advantages in the construction field and help various construction projects to land steadily.
