The basic forms of latticed shells are single-curvature cylinders, double-curvature spheres, and hyperbolic paraboloids. Many interesting new shapes can be generated by intersecting and combining these basic forms. The art of intersection and combination is one of the important tools in the design of latticed shells. In order to fulfill the architectural and functional requirements, the load-resisting behavior of the structure as a whole and also its relation to the supporting structure should be taken into consideration.
For cylindrical shells, a simply way is to intersect through the diagonal as shown in Figure 1a. Two types of groined vaults on a square plane can be formed by combining the corresponding intersected curve surfaces as shown in Figures 1b and c. Likewise, combination of curved surfaces intersected from a cylinder produce a latticed shell on a hexagonal plan as shown in Figure 1d.
Figure:1 Intersection and combination of cylindrical shells
For spherical shells, segments of the surface are used to cover planes other than circular, such as triangular, square, and polygonal as shown in Figure 2a, b, and c, respectively. Figure 2d shows a latticed shell on a square plane by combining the intersected curved surface from a sphere.
Figure:2 Intersection and combination of spherical shells
It is usual to combine a segment of a cylindrical shell with hemispherical shells at two ends as shown in Figure 3. This form of latticed shell is an ideal plan for indoor track fields and ice skating rinks.
Figure:3 Combination of cylindrical and spherical shells.
Different solutions for assembling single hyperbolic paraboloid units to cover a square plane are shown in Figure 4. The combination of four equal hypar units produces different types of latticed shells supported on a central column as well as two or four columns along the outside perimeter. These basic blocks, in turn, can be added in various ways to form the multi-bay buildings.
Figure: 4 Combination of hyperbolic paraboloids.