Calculation method for shear bearing capacity of steel-concrete composite shear wall

The low cycle loading experiments of 24 steel-concrete composite shear walls (hereafter referred as SC shear walls) dominated by shear failure were analyzed, and results show that the shear failure of SC shear walls is characterized by the crush of the diagonal concrete struts in compression or the fracture of the diagonal steel stripes in tension; in the absence of axial load, the web concrete cracks at an angle of 45°, and the buckling of the surface steel plates occurs at an angle of 45°; the axial load enhances the shear capacity of SC shear walls; as the shear-span ratio is smaller than 0.85, the reduction of the shear-span ratio increases the shear capacity, and when the shear-span ratio is greater than 0.85, the increase of shear-span ratio has little influence on the shear capacity. In this paper, a strut and tie mechanism for calculating shear capacity of SC shear walls without axial load is proposed, assuming the steel plates as tensile stripes and the concrete as compressive struts at an angle of 45°, respectively. Based on this model, the equation for shear capacity of SC shear walls is derived, and the influence of axial load is considered. And the form of the equation is in consistency with the equations in the Chinese codes for other kinds of shear walls.