Curved truss connector for freeform single-curved concrete sandwich shell: Analytical model

Concrete sandwich shell (CSS) is a new type of freeform single-curved sandwich structure, which can provide multi-functionality of loading-carrying, insulation, and vibration reduction. It consists of exterior layers enclosing a functional layer connected together using shear connectors. Truss shear connectors have received extensive attention due to their excellent properties, but can only be used in flat sandwich panels. This paper proposes a closed form solution to predict the stiffness of CSS with curved truss connectors. To this end, an analytical model is constructed to calculate the equivalent shear modulus ( G eq ) using the energy method, based on which the shear stiffness of the curved truss connectors is obtained. Next, the accuracy of the analytical model is validated using prior experimental test and Finite Element models, showing the feasibility of using curved truss connectors for CSSs. Finally, parametric study is conducted using the analytical model to investigate the effect of vertex angle on G eq , based on which the optimal vertex angle for different configurations of the CSSs are obtained. The analytical model and optimization method proposed in this study can assist in designing optimal truss connectors for CSSs with different dimensions, resulting in more cost-effective structures. • Innovative curved truss connectors are proposed for freeform single-curved concrete sandwich shells (CSS). • An analytical model accurately predicts the equivalent shear stiffness of the curved connectors. • Optimal vertex angles are identified for maximum stiffness in CSSs. • The effect of connectors and CSS dimensions on the overall shear stiffness is presented.