1.The basic content of the grid/space frame structure
The mesh frame can be divided into two kinds of nodes: welded mesh and bolt mesh. The flat mesh plane shape is flexible and can be designed into various shapes. According to the setting of the rod, it can be divided into: cross truss system, four-angle cone system, triangle cone system and other systems. When the string bar of the grid is vertical to the boundary, it is called the grid, and when the boundary is called the grid. Countries around the world have successfully built many grid structures in large and medium-sized roofs, such as the Expo in Canada and Japan, the Congress Hall of Chicago and the hangar in London, the plane size is very large, and the total amount of steel used is relatively economical. The former Soviet Union also adopted prestress in the grid. In short, the grid structure has become one of the new structures more commonly used in the modern world.
2. grid frame / space frame structure composition form
The first category is divided into three categories: the first type consists of two orthogonal grid truss, double diagonal grid rack and triple grid rack. The second category consists of four-angle cone units, four-angle cone grid, four-diagonal cone grid and the third category consists of three-angle cone units with triangular cone mesh frame and honeycomb triangular cone grid. Shell frame structure according to the shell form is mainly cylindrical shell frame, spherical shell frame and double curved parabolic shell frame. Network frame structure according to the material used in the steel network frame, reinforced concrete network frame and steel and reinforced concrete composite network frame, among which the steel network frame is used more.
3. Design and structure of grid frame / space frame structure
The rod cross-section of the network frame structure shall be determined according to the strength and stability calculation. In order to reduce the calculated length of the pressure bar and increase its stability, measures such as additional reseparation rod and support rod can be adopted. The nodes of plate frame and double shell grid frame made of steel mainly include three forms: cross board node, welded hollow ball node and bolt ball node. Cross plate node is suitable for the grid structure of steel rod, connecting the rod and node plate are welded or high strength bolts. Hollow ball nodes and bolt ball nodes are suitable for the grid structure of steel pipe rod. The nodes of the single-layer shell-type grid frame should be able to withstand the bending internal force. In general, the steel consumption of the node accounts for 15~20% of the steel consumption of the whole steel grid frame structure.
Post time: Aug-29-2022