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Nexus Netw J (2014) 16:89107 DOI 10.1007/s00004-014-0172-1
RESEARCH
Udo Thnnissen
Published online: 6 March 2014 Kim Williams Books, Turin 2014
Abstract In order to span longer distances than the length of the available timber beams the structural principle of mutually supporting beams was used in vernacular buildings and in studies by numerous architects and scientists. Although the generating rules are simple, the control of these structures has to date proven to be very complex because of the reciprocal dependency of the elements. The paper describes the development of a digital tool that shall facilitate the design of these structures and enhance the spectrum of architectural applications. The structural conguration of an assembly is constituted by means of a form-nding process, which is based on the individual members and its relations. Several parameters for these members enable the user to respond to contextual conditions such as plan form, height and number of supports, and to gradually rene the output. The report ends with the description of three applications in which several wooden materials and various forms of fabrication have been tested.
Keywords Reciprocal structure Spatial structures Structural morphology
Timber constructions Form-nding Morphogenesis
History of construction
Introduction
Historical roots
When the designer Graham Brown rediscovered the structural principle in 1987 he renamed it the Reciprocal Frame (Brown 1989). In the various studies on this kind of spatial structure it has been termed differently: mutually supporting beams
U. Thnnissen (&)
D_ARCH ETH Zurich, HIL G57, Wolfgang-Pauli-Str. 15, 8093 Zrich, Switzerland e-mail: [email protected]
A Form-Finding Instrument for Reciprocal Structures
90 U. Thnnissen
(Brown 1989), lever-beam structures (Bertin 2002), and mutually supported element systems (Rizzuto 2007). The term nexorades was introduced by Baverel (2000).
Although very few built testimonies are remaining it is assumed that the principle of reciprocity has been known for a very long time and that it has been used to bridge larger spans with short interlocking beams. History records the presence of similar reciprocal constructions in oriental and occidental cultures, but their evolution is not linear and they are mostly unrelated to each other.
An extensive overview of the studies of architects, scientists and mathematicians, and realised buildings and applications has been made by Popovic Larsen (1996, 2008, 2009) and Pugnale and Sassone (2014).
Fundamentals of...