# Static Bearing Capacity Investigation of a Novel Prefabricated Light-Steel Beam-Column Connection
## 3 Experimental Results  
### Deformation and Failure Characteristics  
For all specimens, global deflection was observed. Figure 12a-h shows typical local-failure modes of the eight specimens. Table 2 summarizes the local failure modes for each specimen. For the tested specimens, four types of local failure modes were observed, including local column buckling, fillet-weld fracture, U-connector buckling, and local buckling of the slotted region of the chord under compression.  
\begin{table}
\begin{tabular}{c c c} \hline
**Specimen** & **Sleeve Tube** & **Deformation and Failure Characteristics** \\ \hline JU60-1 & No & Truss-beam global deflection; local column buckling; fillet-weld fracture \\ JU60-2 & Yes & Truss-beam global deflection; fillet-weld fracture \\ JU60-3 & No & Truss-beam global deflection; local column buckling; local buckling of the slotted region of the below chord \\ JU60-4 & Yes & Truss-beam global deflection; fillet-weld fracture \\ JU100-1 & Yes & Truss-beam global deflection; U-connector buckling \\ JU100-2 & No & Truss-beam global deflection; local buckling; local buckling of the slotted region of the below chord \\ JU100-3 & Yes & Truss-beam global deflection; U-connector buckling \\ JU100-4 & No & Truss-beam global deflection; fillet-weld fracture \\ \hline \end{tabular}
\end{table}
Table 2: Summary of the global and local failure modes.  
Figure 11: Testing rig.  
Figure 12: Cont.  
Figure 12: Local deformation and failure characteristics of the eight specimens. (**a**) JU60\(-\)1, (**b**) JU60\(-\)2, (**c**) JU60\(-\)3, (**d**) JU60\(-\)4, (**e**) JU100\(-\)1, (**f**) JU100\(-\)2, (**g**) JU100\(-\)3, (**h**) JU100\(-\)4.  
Local column buckling was observed in specimens JU60-1, JU60-3, and JU100-2, as shown in Figure 12a,c,f. Columns of these specimens were without the sleeve tube and very vulnerable to local compressive loading transferred from the below chord of the truss beam.  
Fillet-weld fracture was observed in specimens JU60-1, JU60-2, JU60-4, and JU100-4, as shown in Figure 12a,b,d,h. Fillet-weld fracture is mainly attributed to poor welding quality and tension stress acting on the weld transferred from the upper chord of the truss-beam. Therefore, welding quality between the channel connector and the column (or the sleeve tube) should be guaranteed in engineering practice.  
U-connector buckling was only observed in specimens JU100-1 and JU100-3, as shown in Figure 12e,g. Columns of the two specimens were locally reinforced by the sleeve tube. In addition, the fillet welds between the channel connectors and the sleeve tubes of the two specimens were sufficiently strong. Therefore, loading applied to specimens JU100-1 and JU100-3 was much higher than that applied to other specimens. U-connector buckling appears to indicate a higher load-bearing capacity for the proposed light-steel beam-column connection.  
Local buckling of the slotted region of the below chord has been observed in specimens JU60-3 and JU100-2, as shown in Figure 12c,f. This is probably due to the initial geometry imperfection generated in the slotting process and the distortion of the side wall of the chord's slotted region introduced in the assembly process. Therefore, it is necessary to control the deformation of the side wall of the slotted region of the chord during slotting and assembly processes.