Steel structure is the main structure of steel production,  it is one of the main types of building structure. The characteristics of the steel is high strength, light weight, good integral rigidity, deformation ability, so it can the construct large span and super high, super heavy buildings,with good homogeneous and isotropic material, belongs to the ideal elastic body, which is the most suitable for the basic assumptions of the general engineering mechanics. and its good toughness, large deformation can well withstand dynamic loads. Its short construction period and high degree of industrialization can specialized in the production of high degree mechanization.