Strength assessment of curved steel-concrete-steel sandwich shells with bolt connectors under concentrated load

•Four curved SCS shells subjected to concentrated load were experimentally studied.•Failure mechanism and types of curved SCS shells were summarized.•Parameters affecting strength of curved SCS shells were numerically investigated.•Analytical models of curved SCS shells subjected to concentrated load were proposed. In this study, experimental works on four curved steel-concrete-steel (C-SCS) sandwich shells were carried out to assess their behaviors when subjected to concentrated loading with a 100-mm diameter hemispherical steel hammer through analyzing the failure mode, load–displacement relationship, strain, and deformation. The influences of the concrete and steel plate thicknesses, shear connector spacing, and rise–span ratio were numerically investigated. The results showed that the ultimate strength of C-SCS shells was improved with increasing concrete and face steel plate thicknesses and with decreasing shear connector spacing. The optimal rise-span ratio was found to be between 0.25 and 0.33. Moreover, to predict the nominal yield strength and the ultimate strength of C-SCS shells, an analytical model was developed, which matched well with the experimental and FE results. This analytical model can be used as a quick method to calculate the resistances of C-SCS shells under concentrated loading by a hemispherical steel hammer.