First of all, from the connection method. 1, mesh structure nodes are regarded as articulated, usually with bolts. 2. Steel nodes are regarded as rigid joints, usually with welding. Second, from the use of materials and forms. 1、Steel structure is from the steel structure material 2, the grid is from the structural form There can be steel mesh frame, aluminum alloy mesh frame and so on, but in practice, steel mesh frame is mostly used. In addition to steel mesh frame, there are also steel frame, steel portal frame and other forms of steel structure. Third, in terms of structural system. 1. Steel mesh frame is a space structure system, and the overall force and space deformation should be considered in the calculation. 2. Steel truss is similar to plane steel truss, which is a one-way force structure, as long as the strength and stability in the plane are calculated, the stability outside the plane mainly relies on the braces and bollards. Advantages of mesh-shell structure Mesh-shell structure is a net-like shell structure, or a curved mesh structure, its shape is shell, its composition is grid-like, it is a gridded shell, and it is also a shell-shaped mesh. A, the characteristics of the mesh shell structure (1)The rods of the mesh-shell structure mainly bear axial force, the internal force distribution of the structure is relatively uniform, and the stress peak is small, so it can give full play to the material strength. (2) Because it can be used in various shell structure curved form, in appearance can be as rich as the thin shell structure, whether it is the building plane or building shape, mesh shell structure can give designers full design freedom and imagination space, by making the steel structure dynamic contrast, light and dark contrast, virtual contrast, the architectural beauty and structural beauty of the organic combination, so that the building is easier to coordinate with the environment.Steel frame mesh structure is a kind of steel structure and belongs to the same type of steel structure. But the difference between steel frame mesh structure and steel structure lies in the way of connection, the use of steel materials and structural form and structural system.(3)Since the size of the rods is small compared with a whole mesh-shell structure, the mesh-shell structure can be approximated as an isotropic or anisotropic continuum, and the results of analysis of reinforced concrete thin-shell structure can be used for qualitative analysis. (4) The rods of the grid in the mesh-shell structure can be replaced by straight rods instead of curved rods, i.e., folded surfaces instead of curved surfaces, and if the rods are properly arranged and constructed, they can have good force performance similar to that of the thin-shell structure. At the same time, it is convenient for factory manufacturing and on-site installation, and has the same superiority as the flat grid structure in structure and construction method. Generally speaking, single-layer shell can be used for small and medium span (generally below 40m) and double-layer shell for large span. Single-layer shell has better technical and economic indexes because of less rods, light weight, simple nodes and convenient construction, but the single-layer shell surface has poor external stiffness and stability, and various factors will have obvious effects on the internal force and deformation of the structure, so attention must be paid to the arrangement of structural rods, the selection of roofing materials, the determination of calculation mode, the implementation of structural measures and the construction and installation of the structure. The double-layer mesh shell can withstand certain bending moment and has high stability and load force. When the roof needs to install various equipment and piping such as lighting, audio, U-tone, etc., the choice of double-layer mesh can effectively use the space completely, convenient ceiling or ceiling structure, economic and reasonable, double-layer mesh shell according to the thickness of different, there are equal thickness and variable thickness of the points.