Utilising the inherent elasticity of their flexible components, bending-active struc-tures can easily be produced from planar or linear components. Although the components and their fabrication can be very simple, the deformation behaviour is often complex and can result in complex structural geometries. Parametric tools allow modelling such geometries by including material properties and behaviour early on in the design process. While this can potentially lead to an entirely new structural and morphological design vocabulary, functional requirements often demand regularity and compatibility from the structure and its components. This paper presents an approach for the development of bending-active kit- of-parts systems. Consisting of regular sets of identical or compatible components, these systems generate apparent geometric complexity though very simple geometric patterns and component connectivity. The resulting structures are reconfigurable and can be adapted to multiple uses, locations and spatial requirements. Theoreti-cal insights are supported by two applied cases: reciprocal bending-active structures and kinetic curved-line folding structures. Both use the flexibility of their components to develop structural diversity through a simple geometric system. Illustrated by two built structures, these cases show how a well- integrated design that considers manufacturing and assembly can lead to an efficient construction process. Moreover, using reversible connections, the structures allow reuse and even reconfiguration.@en

While transformable structures allow rapid assembly, reuse and reconfiguration, their technical complexity and related production or cost issues often hinder architectural application. Yet, vernacular or nomadic structures, like teepees or yurts, show how reversibility and transportability can be achieved with low-tech structural systems. The project presented in this paper is part of a broader research that investigates how material understanding and manipulation through elastic deformation can contribute to the development of low-tech and rapidly assembled kit-of-parts structures. More specifically, the ReciPlyDome project combines the concepts of bending-active and reciprocal structures. The parametric design and modelling of the system are based on regular polyhedra to guarantee uniformity and allow reconfiguration of the components. While this works from a design perspective, the structural performance is limited by the flexibility of the components. Therefore, we developed a double-layered component to increase the structural height and improve the stiffness of the structure. Preliminary FEM analyses provide assessment of this layering and stress stiffening, i.e. the stiffening effect of the residual stress. A full-scale prototype illustrates the rapid and low-tech manufacturing and assembly process. Through design, analysis and finally construction, this project illustrates the potential of active-bending in developing more low-tech and rapidly assembled structures.@en

Reciprocal Frame (RF) Structures are three-dimensional grid structures consisting of mutually supporting beams, where no more than two beams are connected at a time adding to simplicity of assembly and construction. The ReciPlyDome is a novel structural system based on utilizing bending-active principles and combining them with RF polyhedral morphologies and simple connections. The result is a lightweight plywood kit-of-parts dome, fabricated from flat plywood panels, cut and pre-bent to form the active-bent dome structure designed for disasembly. ReciPlySkin is a step further in the development and is a partially enclosed shelter structure clad with a membrane attached internally to the plywood beams of the ReciPlyDome. Building on the work already done on RF emergency shelters, this paper describes the ReciPlyDome and ReciPlySkin governing principles in the context of transformability. It presents the challenges and opportunities of these structures outlining the methods and process needed for their development. More specifically the investigation, design, optimization, fabrication and construction process of a full-scale dome demonstrator exhibited at the recent Circular Economy exhibition in Denmark, are shown. A reflection on how to develop the principles further is offered with some further research and design directions identified. Lastly, possible applications are also discussed.@en

Bending-active reciprocal structures consist of elastically bent beams in a mutually supporting weave pattern in which each connection joins only two beams. Aside from the advantages for fabrication and assembly, this system has an extensive geometric potential, allowing reuse and reconfiguration. However, the load-bearing behaviour of these structures is limited by the required flexibility of the components. This paper discusses the impact of geometric parameters on the stiffness of bending-active reciprocal geometries for two cases: single-layered domes and double-layered components. It concludes by illustrating the use of the double-layered component for the development of a kit-of-parts structure: the ReciPlyDome. Thanks to the elastic capacity of the components and the very simple connections, the ReciPlyDome can be very easily and rapidly assembled and manufactured. This in contrast with the high technical complexity of many other kit-of-parts or grid structures. The analyses underline the importance of the form-force relationship when developing bending-active reciprocal structures and show the potential of active bending for the development of pre-assembled beam components. This research is framed within the wider scope of developing lightweight, transformable and temporary structures.@en

As mutually supported beam structures, reciprocal frames limit the number of components that are joined at each connection to two. However, this system of intermediate connections introduces undesirable bending moments in the beam elements. By utilising elastic deformation to create curved geometries, bending-active structures show the potential of bending as a formation process. Moreover, the curved geometries showcase an increased resistance to bending. Despite the apparent potential, only a few geometric explorations of bending-active reciprocal structures exist. Therefore, we investigated the principle by developing a design methodology based on polyhedral shapes. As this work is part of a research on transformable, rapidly assembled structures, the focus lies on simplicity of the connections, uniformity of the components and reconfigurability. This paper discusses the development of a kit of parts of reciprocal bending-active components based on a selection of polyhedral dome types. To simplify the assembly of the structures and avoid the manual bending of the components on site, we introduce the concept of a double-layered, pre-bent component. Finally, this paper presents the development, fabrication and assembly of the ReciPlyDome, a full-scale prototype of a bending-active reciprocal dome with double-layered components. Preliminary analyses of the load-bearing behaviour show the potential of these systems for material-efficient, lightweight structures. The research presented in this paper contributes to the understanding of bending-active reciprocal frames as a structural principle for temporary and rapidly assembled structures.@en