Conceptual Design from Precedents and Holistic Performance Assessment of Free-edge Gridshells

Gridshells are lightweight structures worldwide adopted thanks to their high efficiency resulting from their form-resistant structural behaviour. The gridshell structural efficiency can be compromised by the presence of free edges, which lead to the occurrence of flexural effects prevailing on the typical gridshell membrane-like behaviour. Four different design principles addressing such issues for shell-like structures emerge from the literature. The purpose of this paper is to evaluate and compare the effectiveness of the identified design principles for free-edge gridshells. To this aim, the present work takes as case study the barrel vault proposed within the FreeGrid benchmark. Seven Conceptual Design Solution Gridshells are conceived through a design-from-precedent approach based on the identified design principles. Three traditional Design Solution Gridshells are tested based on common strategies for gridshells with unconstrained edges. Four novel Design Solution Gridshells are proposed in analogy to strategies more commonly adopted in shell structures. Their overall performance is assessed in terms of structural behaviour, buildability and sustainability. The obtained results shed some light on the mechanical behaviour of each solution. Moreover, the performance metrics allows to identify the best performing solution in the conceptual design phase so to eventually refine it within the final design phase.