## 1 Introduction
The extensive research works focused on the seismic behavior of the SC composite wall under in-plane cyclic loading; several research studies on the seismic behavior of SC composite beams under out-of-plane cyclic loading were carried out. [PERSON] et al. [15,16] carried out a quasi-static test to compare the flexural behavior of the SC composite beams under out-of-plane cyclic and monotonic loadings. The specimens were fabricated according to the stipulates in JEAC 4618-2009 [2] and KEPIC-SNG [17]. The experimental results showed that the failure mode of SC composite beams under cyclic loading was brittleness, and the load capacities of SC composite beams under cyclic loading were lower than those under monotonic loading. The experimental results indicated that the interfacial slip of studs could significantly affect the flexural behavior of the SC composite beam under out-of-plane cyclic loading. [PERSON] et al. [18] compared the flexural behavior of the SC composite beam and RC beam under out-of-plane cyclic loading. After reaching ultimate capacities, the capacities of SC composite beams decreased rapidly. The RC beam shown significant ductility, and the ultimate displacement was far more than that of the SC composite beam. [PERSON] et al. [19] investigated the influence of the number of shear connectors on the seismic behavior of the SC composite beam under out-of-plane cyclic loading. The SC composite beam with sufficient shear connectors had significant ductility, but the SC composite beam with fewer shear connectors had significantly lower ultimate displacement. It indicated that the design method of the shear connectors is crucial for the seismic behavior of the SC composite beam subjected to out-of-plane cyclic loading. [PERSON] et al. [20] compared the flexural behavior between a SC composite beam with 42 tie-bars and a SC composite beam with 42 tie-bars and 56 studs. The experimental results indicated that the interfacial shear distribution can be affected by the shear connection ratio, and the added studs did not significantly improve the ductility and energy dissipation capacity of the SC composite beams under out-of-plane cyclic loading. It indicated that the design method of shear connectors based on the shear connection ratio can be imperfect for the SC composite beam. Thus, this paper investigated the interfacial shear distribution of SC composite beams under cyclic loading and proposed the design method for tie-bars. Firstly, the finite element model of SC composite beam was developed and verified. Meanwhile, two rules on the interfacial shear distribution of shear connectors are proposed. Secondly, the flexural behavior of SC composite beams with different shear connection ratios was analyzed, including load-displacement curves, internal force, interfacial slip distribution, and interfacial shear distribution. Thirdly, the influences of shear span ratio, shear stiffness, and number of tie-bars on the minimum shear connection ratio of SC composite beam under cyclic loading were investigated. Finally, based on the current research results, the simulation results in this paper, and stipulations in existing codes, the design method for tie-bars in SC composite beams subjected to out-of-plane cyclic loading is proposed.