Classification of steel space frame structure

 Steel space frame is a space structure made of multiple rods connected by nodes according to a certain grid form. Constitutes the basic unit of steel space frame has triangle cone, triangular, square, truncated quadrangular cone, etc., by these basic units can be combined into a plane shape of the trilateral, quadrilateral, hexagonal, circular or any other shape. With space force, light weight, rigidity, good seismic performance and other advantages; can be used as a gymnasium, theater, exhibition halls, waiting halls, stadium bleachers canopy, hangars, two-way columns of steel mesh structure from the workshop and other buildings of the roof.

　　It can be divided into double-layer plate-type net frame structure, single-layer and double-layer shell-type net frame structure. The rods of plate-type net frame and double-layer shell-type net frame are divided into upper chord rod, net frame lower chord rod and web rod, which mainly bear tensile force and pressure; the rods of single-layer shell-type net frame, in addition to bearing tensile force and pressure, but also bear bending moment and shear force. At present, the vast majority of China's net frame structure adopts plate-type net frame structure.

　　Mainly divided into three types: one type is composed of plane truss system, there are four forms of two-way orthogonal orthotropic net frame, two-way orthotropic diagonal net frame, two-way diagonal diagonal diagonal net frame and three-way net frame; the second type is composed of quadrangular cone unit, there are five forms of orthotropic quadrangular cone net frame, orthotropic pumping quadrangular cone net frame, diagonal quadrangular cone net frame, tessellations quadrangular cone net frame and star quadrangular cone net frame; the third type is composed of triangular cone units, there are The third type consists of triangular cone unit, there are three forms of triangular cone net frame, pumping triangular cone net frame and honeycomb-shaped triangular cone net frame. Shell-type rack structure according to the shell surface form mainly has column surface shell-type rack, spherical shell-type rack and hyperbolic parabolic surface shell-type rack. Net frame structure according to the material used in steel net frame, reinforced concrete net frame and steel and reinforced concrete composed of a combination of net frame, of which the steel net frame used more.

　　The cross-section of the rods of the steel net frame structure should be determined according to the strength and stability calculation. In order to reduce the calculated length of the pressure rod to increase its stability, can be used to increase the re-split rod and support rods and other measures. The nodes of plate type net frame and double shell type net frame made of steel mainly have three forms: cross plate node, welded hollow ball node and bolt ball node. The cross plate node is applicable to the net frame structure of steel bars, and the connection between bars and node plate adopts welding or high-strength bolt connection. Hollow ball nodes and bolted ball nodes are applicable to the net frame structure of steel pipe rods. The nodes of single-layer shell-type net frame should be able to withstand the bending internal force, in general, the steel consumption of the nodes accounts for 15-20% of the steel consumption of the whole steel net frame structure.