## 7 Conclusions  
This paper designed a novel FHSB T-stud connection based on the structural features in the anchorage zone of a CSS-enhanced PSC-CBGB. Then, static load tests were conducted on 21 specimens with different shear-compression ratios, followed by finite-element modeling of the specimens. The specimens were investigated and compared in the failure mode, initial friction load and ultimate strength. After that, FEM based numerical simulation was performed to analyze the effects of multiple parameters on the initial friction load and the ultimate strength. The analysis results were used to evaluate the load-bearing capacity of the FHSB T-stub connection. The main conclusions are as follows:  
1. Under the combined effects of shear and compression, the FHSB T-stub connection mainly suffered from bolt shearing failure. The load-displacement curve generally covered four stages: the elastic stage, yield stage, hardening stage and failure stage. If the shear-compression ratio is small and the friction coefficient is large, the ultimate strength of FHSB T-stub connection equals its initial friction load. In this case, the load-displacement curve for the connection only contained the elastic stage and failure stage.
2. The finite-element model proposed in this paper is suitable to study the mechanical behavior of FHSB T-stub connection under both shear and compression.  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Source of Difference** & **DF** & **SS** & **MS** & **F** & \(p\) \\ \hline Regression & 1 & 126.8280 & 126.8280 & 4199.9847 & \textless{}0.0001 \\ Residual & 46 & 1.3891 & 0.0302 & - & - \\ Total & 47 & 128.2170 & 2.7280 & - & - \\ \hline \hline \end{tabular}
\end{table}
Table 6: Results of ANOVA.  
Figure 25: The relationship between the initial friction load and different parameters.  
3. The friction coefficient and shear-compression ratio had great impacts on the initial friction load, improved anti-slip coefficient and ultimate strength. The larger the friction coefficient, the smaller the shear-compression ratio, and the better the anti-slip bearing capacity of the FHSB T-stub connection.
4. The initial friction load and ultimate strength increased linearly with the growing bolt diameter. For every 1 mm increase in bolt diameter, the initial friction load increased by about 10%, while the ultimate strength increased by about 8.5% within a 16-22 mm-diameter.
5. The initial friction load increased linearly with the increase of clamping force, while the ultimate strength showed a linear decline. For each 10% increase/decrease of the design clamping force within 16-22 mm-diameter bolts, the initial friction load decreased/increased by 7.8%, while the ultimate load remained basically the same.  
The proposed formula of shear capacity and self-lock angles of FHSB T-stub connection could be applied to the design of CSS-enhanced PSC-CBGBs and diagonal bracing. However, this paper only studied the friction coefficient, shear-compression ratio, bolt diameter and clamping force within a certain range, and the conclusions obtained had a certain scope of application. In addition, the influence of plate thickness and nut corrosion damage on the mechanical properties of the FHSB-T stub connections under shear and compression, and the variation law of friction coefficient after first slipping need to be further studied.  
Conceptualization, G.X. and Y.W.; methodology, G.X.; software, Y.D., L.W.; validation, G.X., L.W. and Y.D.; formal analysis, Y.D.; investigation, G.X., Y.Z.; resources, G.X.; data curation, G.X.; writing--original draft preparation, G.X., W.Z.; writing--review and editing, G.X.; visualization, Y.D., G.X.; supervision, Y.W.; project administration, Y.W.; funding acquisition, Y.W., G.X. All authors have read and agreed to the published version of the manuscript.  
This research received no external funding.  
The authors declare no conflict of interest.