Optimization Strategies for Grid Shells: The Role of Joints

Structural optimization techniques are being usefully employed for the design of large grid shell structures. Indeed, thanks to the use of innovative strategies and mathematical algorithms, it is possible to combine different design parameters and structural requirements in a global process finalized to obtain solutions optimized for structural and architectural aspects. In the case of grid shells, a relevant role is played by the joints, which particularly influence both the local and the global stability. Nevertheless, few studies specifically concerning the role of joints in the optimization of grid shell structures are currently available. The aim of the study here presented is to carry out efficient optimization strategies for grid shell structures that specifically account for the role of joints. In particular, considering the possibility of having joint configurations able to offer different constraint conditions for members, the proposed strategies combine the common sizing optimization technique of members with the possibility to vary the configuration of joints. As shown in the paper, the proposed optimization strategies allow obtaining lighter solutions with respect to the ones obtained by only using the sizing optimization technique, particularly when global stability represents the governing phenomenon.