## Materials and Methods  
### Specimen Design  
In the test, eight anchored blind-bolted extended end-plate joints between CFST columns and steel beams were designed and tested. The main parameters of the specimens are listed in Table 1, and the basic configurations of the joint are shown in Figure 2. The specimen parameters include the steel tube wall thickness in the panel zone, end-plate thickness, beam section size, local strengthening connection method, blind bolt anchorage method, and stiffeners. A cold-formed square steel tube with cross-sectional dimensions of 200 mm \(\times\) 200 mm \(\times\) 5 mm was used. Grade 8.8 M16 Hollo-Bolts, made in the UK, were adopted as high-strength blind bolts with extended bolt shanks and grade 8.8 anchor nuts at the end, as shown in Figure 1. The embedded depth (\(d_{\text{emb}}\)) for the blind bolts was 90 mm, which is the length along the bolt between the inner surface of the steel tube and the bearing surface of the anchor nut. HN350 \(\times\) 175 \(\times\) 7 \(\times\) 11 (mm) H-beam sections were used for specimens SJ-1 through SJ-5, whereas HN300 \(\times\) 150 \(\times\) 6 \(\times\) 9 (mm) H-beam sections used for specimens SJ-6 through SJ-8. For specimens SJ-3 through SJ-8, two C-channels were externally welded in the panel zone to increase the local steel tube wall thickness. Moreover, as shown in Figure 3, the C-channels in SJ-5 were connected to the steel tube by fillet welding only, whereas the C-channels in the other specimens were additionally connected to the steel tube wall through plug welding. In SJ-5, only the bolts were extended, and no nuts were installed on the end of the bolts. The design of the specimens is outlined as follows:  
Specimens SJ-1 versus SJ-3 and specimens SJ-2 versus SJ-4 were used to study the effect of the wall thickness of the steel tube;  
Specimens SJ-1 versus SJ-2 and specimens SJ-3 versus SJ-4 were used to study the effect of the end-plate thickness;  
Specimens SJ-3 and SJ-5 were used to investigate the effect of the local strengthening connection method and anchorage method on joint performance;  
Specimens SJ-3 and SJ-6 and specimens SJ-4 and SJ-7 were used to examine the effect of steel beam sections;  
Specimens SJ-6 and SJ-8 were used to study the effect of stiffeners.  
To install a blind bolt, first, an impact wrench was used for pretightening, and then a torque wrench was used for the final tightening. According to the instructions provided by Lindapter International, a torque of 190 N-m was applied, corresponding to a pretension load of 70 kN. Prior to installing the blind bolt, the nut and the bolt were fixed with glue or a spot weld to prevent the nut from falling off due to vibration during installation or concrete casting.  
\begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline
**Specimen** & **Column** & **Column** & **Beam Section (mm)** & **End-Plate** & **Local** & **Anchorage** & **Stiffener** \\
**Number** & **Section (mm)** & **Length (mm)** & & **Thickness (mm)** & **Reinforcement** & **Method** & **Stiffener** \\ \hline SJ-1 & 250 \(\times\) 5 & 1736 & HN350 \(\times\) 175 \(\times\) 7 \(\times\) 11 & 12 & None & Nut & None \\ SJ-2 & 250 \(\times\) 5 & 1736 & HN350 \(\times\) 175 \(\times\) 7 \(\times\) 11 & 24 & None & Nut & None \\ SJ-3 & 250 \(\times\)