The flat “lattice” (beams and cross members) roofs supported on columns are the most common trellises in our gardens. They are heavy in every sense, materially and visually. Yes, they are easy to make/erect and inexpensive. And these are good reasons why they will continue to be ubiquitous.
However, occasionally we should aim a bit higher and design/build trellises that express contemporary ideas about the geometry of spatial forms. For me this means doing more with less.
The illustrations here show a gridshell pergola. Its surface is synclastic, i.e. having curvatures in the same sense (concave or convex) in all directions through any point. The geometry of this geodesic gridshell is generated by projecting (from the centre) the edges of a cube onto the circumsphere. It is 1/6th of the sphere’s surface. This surface is further subdivided forming a quadrangular mesh following great circle arcs.
Note, a geodesic gridshell lattice cannot be laid out flat, which gives the structure extra stiffness. Structural designs that follow nature’s example, i.e. geodesic principles, will result in obtaining minimal, highly efficient forms which are beautiful, in harmony and at ease with nature.
- Sphere with a geodesic quadrangular pattern.
- Geodesic gridshell supported on four tetrahedra.
- Horizontal projection of the gridshell.
- An aggregate of gridshells.