This paper deals with the design of reciprocal spatial configurations based on the use of planar elements, which are investigated and classified according to their morphological characteristics and potential. Reciprocal structures are generally designed with the use of linear elements. Since their historical conception, at least in Western culture, they...[More]
This paper deals with the design of reciprocal spatial configurations based on the use of planar elements, which are investigated and classified according to their morphological characteristics and potential. Reciprocal structures are generally designed with the use of linear elements. Since their historical conception, at least in Western culture, they have been strictly related to the use of short timber beams to cover large spans. This structural principle is described for instance by Villard de Honnecourt, who drew in his sketchbooks reciprocal grillage assemblies for the construction of floors, between 1225 and 1250, followed by Sebastiano Serlio in 1566, John Wallis in 1695, and it can be still found in several treatises of carpentry, written during the XIX century. From the morphological point of view, reciprocal structures have been generally used to develop bridges, slabs, domes and shells. We could conceptually refer to the first case linear developments. Examples are the so-called ‘Rainbow Bridge’ in Shandong or the Leonardo’s concept for a bridge structure. In the second and third cases we could refer to a two-dimensional development, since they can be conceptually conceived and represented as surfaces. Several examples have been built by the architects Ishii, Kijima and Kan. In architecture, reciprocal structures are rarely used due to a set of practical issues. Their simple technology allow a simple and rapid construction,. However, problems related to spatial complexity, structural calculations and cladding, generally encourage designers in exploring other structural typologies, making their use suitable just for temporary or experimental structures. In this framework, the authors propose a initial study of reciprocal systems based on the use of non-linear elements, i.e. 2D planar panels. Such configurations are classified in this paper according to the shapes and properties of their composing elements. For example: (1) most of the planar elements can generate the same configurations of beam elements; (2) some planar elements can be disassembled in two or more linear elements forming a similar configuration; (3) some planar elements can be composed in order to take advantage of their shape peculiarities, for structural or construction purposes. Configurations belonging to this category could be also referred to the previous ones. The presented categories are supported by drawings and photographs of prototypes, also realized with the contribution of the students of the École des Ponts in Paris (developed during a workshop run by the authors in March 2012) and the University of Melbourne.