The name of grid shell commonly describes a structure with the shape and strength of a double- curvature shell, but made of a grid instead of a solid surface.
These structures can cross large spans with few material.
Through knowledge and understanding of various precedents, the goal is to explore the possibilities of the grid structure and its ability to create space; the relationship with bending stresses, member profiles and joinery techniques.
SUTD Library Gridshell Pavilion by City Form Lab
Building upon a long tradition of catenary structures that use little material to achieve considerable spans, the canopy forms a lightweight timber shell with no columns, beams, or vertical walls. Using computational design and computer controlled fabrication allowed the pavilion’s complex three-dimensional form to be achieved with readily available materials and a streamlined assembly process at minimal cost.
Jow and Rika Mansueto Library
The grid shell structure has a total area of 120 x 240 feet. It is made up of 6-inch-diameter steel pipe laid out in a 6-foot-by-6-foot grid and anchored to a concrete ring foundation. Posts extending up from the intersections of the pipe support anchors that accept the glass panels.
The role of computational design in this research became essential. With the use of parametric tools, such as Grasshopper, we analyzed and developed gridded structures.
Through various iterations we were able to see how certain functions can be performed early on its definition.
Construction takes place in four steps:
First, a flat grid of straight wood members is laid out, making the creation of the connections very easy. Second, staples are used as joints for the grid, but they are not fully fixed to allow some sliding of the laths. Third, the whole grid is wet in order to be able to manipulate the shape into the desired form. Fourth, let dry the grid and connections to get a fixed form (additional support may be needed until it dries completely).
The grid, initially flat, and without any in-place shear stiffness, is deformed elastically to create a double-curved surface. The deformed grid is then braced to gain rigidity and increase the buckling capacity. Sometimes additional support was required to keep the desired form.
The grid pattern that distinguishes the structure benefits from their geometry to become self-standing; and the combined action of shell and arches achieve unique shapes. The final structures we designed have a very organic form that makes them look weightless.
In next phase, we will continue to analyze more grid structures and understand the material properties of wood in order to take advantage of the gridshell.