## 7 Conclusions  
The finite element model of the SC composite beam was developed and verified through a quasi-static test. Two interfacial shear distribution rules and three shear connection ratio levels were proposed. The load-displacement curves, internal force of steel plate and concrete, interfacial shear distribution, and interfacial shear slip distribution of six 3 m long SC composite beams with different shear connection ratios subjected to out-of-plane cyclic loadings were investigated. Based on the simulation results, the definition of minimum shear connection ratio was proposed. Then, 175 SC composite beam finite element models were developed to study the influence of shear span versus depth ratio, the stiffness of the tie-bar, and the number of tie-bars on the minimum shear connection ratio. Finally, a design method for tie-bars in SC composite beams subjected to out-of-plane cyclic loading was developed. The main findings are shown in the following:  
1. The SC composite beam finite element model was developed and verified, and the load-displacement curves from the simulation result coincided well with those from the experimental result. It indicates that the simulation results were accurate and reasonable. 2. Two interfacial shear distribution rules were proposed based on the existing research and verified through the simulation results of the SC composite beam. Three shear connection ratio levels, i.e., low shear connection ratio, middle shear connection ratio, and high shear connection ratio, were proposed, which were determined based on the yield tensile capacity of the steel plate and the shear capacities of the whole tie-bars at the interface. 3. Six SC composite beam finite element models were developed to investigate the influence of the shear connection ratio on the interfacial shear distribution of the SC composite beam. According to the simulation results, the definition of the minimum shear connection ratio was proposed, which indicated that the tension of the tensile steel plate should reach the yield tensile capacity when the SC composite beam reached yield capacity. 4. The minimum shear connection ratio of the SC composite beam decreased with the increase in shear span versus depth ratio; the influence of the stiffness of the tie-bars varied from 50% to 150% of initial stiffness on the minimum shear connection ratio and could be neglected; the number of tie-bars also significantly affected the minimum shear connection ratio when the number of tie-bars was less than 10, but the influence could be negligible when the number of tie-bars was more than 10. 5. A design method of tie-bars in the SC composite beam subjected to out-of-plane cyclic loading was proposed based on the simulation results, existing research, and existing specifications. According to the simulation results, the proposed design method is accurate and reasonable. Figure 15: Load-displacement curves of SC composite beams with different diameter tie-bars. (**a**) 16 mm diameter tie-bar; (**b**) 18 mm diameter tie-bar. **Author Contributions:** Conceptualization, B.L. ; methodology, B.L. and C.L. ([PERSON]); software, B.L. and C.L. ([PERSON]); validation, C.L. ([PERSON]); formal analysis, B.L. ; investigation, B.L. ; resources, B.L. and C.L. ([PERSON]); data curation, B.L. ; writing--original draft preparation, B.L. ; writing--review and editing, B.L. ; visualization, B.L. ; supervision, L.G. ; project administration, L.G. ; funding acquisition, B.L. and C.L. ([PERSON]). All authors have read and agreed to the published version of the manuscript. **Funding:** This research was funded by Scientific Research Fund of Institute of Engineering Mechanics, China Earthquake Administration, grant number: 2021D34; National Natural Science Foundation of China, grant number 51825801, 51878432, and 51908504; School Natural Science Foundation of Suzhou University of Science and Technology, grant number XKZ2020012. **Institutional Review Board Statement:** Not applicable.