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Geodesic gridshells are shell structures made of continuous elements following geodesic lines. Their properties ease the use of beams with anisotropic cross-sections by avoiding bending about their strong axis. However, such bending may arise when flattening arbitrary geodesic grids, which forbids their initial assembly on the ground. This study provides a process to design elastic geodesic gridshells, that is, gridshells that minimise bending moments in both formed and near-flat configurations. The generation process first brings a target geodesic network onto a plane by maintaining arc lengths. The flat mesh is then relaxed to minimise its main curvatures and hence bending moments in its members. The result is an elastic geodesic gridshell that can be assembled flat on the ground and then lifted up into its target surface. The method is applied to the design of six geodesic gridshells made of reclaimed skis. [ABSTRACT FROM AUTHOR]

Direct methods that transform the geometry of a structure and conserve its static equilibrium are of particular interest for designers. They allow the exploration of alternative solutions at minimum computational cost. While parallel transformations (stretch, contraction, and skew) are easily understood and have been in use since long, nonparallel transformations that maintain static equilibrium have not been studied in detail. The contributions of this article are as follows. First, an extensive review of transformation methods maintaining static equilibrium of planar and spatial structures is carried out. Second, an alternative construction of projective transformation is developed as an original set of graphical operations. Third, the benefits and limitations of use of projective transformations are discussed for the first time. This article concludes that (1) projective transformations are of practical interest only for a restricted range of structural applications but (2) can significantly simplify the computational problem of geometric exploration of spatial networks in equilibrium with few or no external forces. [ABSTRACT FROM AUTHOR]

Structural robustness is related to the insensitivity of a structure to local failure, which is linked to the ability of force redistribution. Current approaches—probabilistic, risk-based, deterministic, and energetic—are poorly suited to inform the design of a structure at conceptual stage. Yet robustness issues must be addressed early in the design process, when interaction with the structural model is still feasible. This article explores how geometrical solution domains provide indicators that summarize the ability of a structure to redistribute load paths. Since geometric methods only build on abstract load path networks, directly connected to form and force diagrams, they suit well for early design explorations. This article presents two case studies, shows how geometrical domains provide qualitative and relevant constitutive indicators of structural robustness, and finally compares the results with indices of deterministic and energetic criteria currently proposed in the literature. [ABSTRACT FROM AUTHOR]

This article presents a computational design methodology that integrates generative (architectural) and analytical (engineering) procedures into a simultaneous design process. By combining shape grammars and graphic statics, the proposed methodology enables the following: (1) rapid generation of diverse, yet statically equilibrated discrete structures; (2) exploration of various design alternatives without any biases toward pre-existing typologies; (3) customization of the framework for unique formulations of design problems and a wide range of applications; and (4) intuitive, bidirectional interaction between the form and forces of the structure through reciprocal diagrams. Design tests presented in this article illustrate the creative potential of the proposed approach and demonstrate the possibility for unbiased explorations of richer and broader design spaces during early stages of design, with much more trial and less error. [ABSTRACT FROM AUTHOR]

An introduction is presented in which the editors discuss various reports within the issue on topics including reciprocal diagrams, the connection between mechanisms and self-stress and their relations to form and force diagrams, and the role of graphical computation on structural shapes.