Compared with flat grid structures, grid shells have better load-bearing performance, greater stiffness, smaller self weight, and less steel consumption, making them a better structural type suitable for medium and large-span building roofs.
The common types of mesh shell structures include cylindrical mesh shell, spherical mesh shell, and hyperbolic parabolic mesh shell.
1. Cylindrical mesh shell: a mesh structure with a cylindrical curved surface, which combines the stress characteristics of rod and shell structures. It only has curvature in a single direction and often covers rectangular planes in buildings. There are four types of single-layer mesh shells arranged: unidirectional diagonal bar orthogonal grid, cross diagonal bar orthogonal grid, square grid, and three-dimensional grid. The double-layer grid can be arranged with different grids according to the type of flat grid. The ratio of shell height to wavelength is generally between 1/6 and 1/8. The thickness of the double-layer mesh shell should be 1/20 to 1/30 of the wavelength.
2. Spherical grid shell: used to cover large-span roofs, common grid forms include ribbed, Schweider ribbed, square grid, short-range line, and three-dimensional grid. By cutting the shell surface, spherical mesh shells can be used for roofs of polygonal, rectangular, and triangular flat buildings.
3. Hyperbolic parabolic mesh shell: formed by moving the two ends of a straight line parallel to two fixed wires (straight lines or curves) inclined in space. Single layer mesh shells often use straight beams as members, while double layer mesh shells use straight truss structures, which are orthogonal in two directions to form hyperbolic parabolic mesh shells. This type of mesh shell is mostly used for asymmetric building plans, and the building is novel and lightweight.