The grid structure is a spatial structure composed of multiple members connected by nodes in a certain grid form. It has the advantages of low spatial stress, light weight, high stiffness, and good seismic performance; It can be used as the roof of buildings such as sports halls, theaters, exhibition halls, waiting halls, sports stands, awnings, aircraft hangars, and workshops with large column spacing in both directions. The disadvantage is that there are a large number of members connected to the nodes, and the production and installation are more complex than planar structures.
The cross-section of the members of the grid structure should be determined based on strength and stability calculations. To reduce the calculated length of the compression bar and increase its stability, measures such as adding re splitting bars and support bars can be taken. The nodes of the plate type grid and double-layer shell type grid made of steel mainly include three forms: cross plate nodes, welded hollow ball nodes, and bolted ball nodes. The cross plate node is suitable for the grid structure of steel members, and the connection between the members and the node plate is made by welding or high-strength bolts. Hollow sphere nodes and bolted sphere nodes are suitable for the grid structure of steel pipe members. The nodes of a single-layer shell type truss should be able to withstand bending internal forces. Generally, the steel consumption of nodes accounts for 15-20% of the total steel consumption of the entire steel truss structure.