Experimental Investigation of the Static and Dynamic behaviors of 3D-Printed Shell Structures

. Over the last years, several optimization strategies were conducted to find the optimal shape minimazing internal stress or total weight (volume) of shell structures. In recent times, this structure typology gained a great importance among researchers and the scientific community for the renowed interest in the form-findind optimization of column-free space solution for large span roofing constructions. In the present paper, a form-finding of a shallow grid shells was introduced basing on the multy-body rope approach (MRA) for the definitions of vault shapes and different hole percentage. In order to obtain an experimental validation, a physical model was reproduced at the laboratory scale performing ad hoc measurements to compare the observed respect to the simulated behaviour. A 3D printing procedure based on the Fuse Deposition Modeling (FDM) technique in polylactide (PLA) material was used to realise form-works of the cement based blocks of the scaled prototype. Several static and dynamic load configurations are investigated, collecting into a sensitivity analysis the parameters which mainly affect the structural behaviour. To simulate earthquake ground motion an assigned frequency range as dynamic input to the structure was provided by a shaking table. Finally, some preliminary considerations of the dynamic response of the model were provided testing the robustness of the form-finding approach when horizontal load are taken into account. The final geometric configuration of the vault is obtained by analysing the effect of some chosen parameters such as the lowering degree (defined as the ratio between the maximum span D and h, defined as the height of the vault), the slack coefficient of the original hanging net and the hole percentage (HP) of the covering surface. The final shape and the pierced pattern were analysed by the MidasGen©software under static and seismic load pattern configuration once constraint conditions were fixed.