## 4 Experimental Results and Analysis
### Ductility  
The ductility of a structure is evaluated using the amount of energy that may be dissipated through plastic deformations. The ductility concept is used in the practice of seismic-resistant design and allows, depending on the used structural system, for a reduction in the seismic forces and can control the level of damage produced during medium and strong earthquakes. The displacement ductility of the specimen is represented by the displacement ductility factor \(m\), which is defined as the ratio of ultimate displacement \(d_{u}\) to the yield displacement \(d_{y}\). These displacements are determined from the envelope curve of the hysteresis loops (Figure 11). The ultimate displacement is defined as displacement corresponding to a 15% drop in the loading capacity. The yield displacement of a  
Figure 15: Cumulative energy dissipation versus drift. \begin{table}
\begin{tabular}{c c c c c} \hline  & \multicolumn{2}{c}{**SC1**} & \multicolumn{2}{c}{**SC2**} \\ \cline{2-5}  & **Cycle 1** & **Cycle 2** & **Cycle 1** & **Cycle 2** \\ \hline
**Drift (\%)** & \multicolumn{4}{c}{**Cumulative Energy Dissipation**} \\ \hline
0.25 & 0.049 & 0.058 & 0.04 & 0.046 \\
0.5 & 0.321 & 0.398 & 0.24 & 0.276 \\
0.75 & 1.213 & 1.402 & 0.996 & 1.175 \\
1 & 3.244 & 3.63 & 2.865 & 3.258 \\
1.25 & 6.64 & 7.22 & 5.978 & 6.562 \\
1.5 & 11.29 & 12.08 & 10.38 & 11.14 \\
1.75 & 17.81 & 18.77 & 16.31 & 17.31 \\
2 & 28.44 & 29.7 & 25.31 & 26.75 \\
2.25 & 43.2 & 44.64 & 38.27 & 40.08 \\
2.5 & 62.36 & 63.92 & 55.48 & 57.53 \\
3 & 89.67 & 91.18 & 81.03 & 83.03 \\
3.5 & 125.68 & 127.48 & 116.08 & 118.34 \\
4 & 170.58 & 172.54 & 162.08 & 164.54 \\
4.5 & 224.38 & 226.84 & 219.68 & 222.84 \\
5 & 287.78 & 290.54 & 290.19 & 294.24 \\
5.5 & 361.18 & 364.24 & 373.82 & 378.76 \\ \hline \end{tabular}
\end{table} 
Table 5: Cumulative energy dissipation. specimen is determined based on the general yielding method, as shown in Figure 16. An elastic behavior occurs where the initial tangent stiffness intersects the horizontal line passing the peak strength at point A. A vertical line passing the point A intersects the load-displacement envelope curve at point B. A secant line passing the point O and the point B intersects the horizontal peak strength line at point C. A vertical line passing point C intersects the envelope curve at point D, which is the yielding point [17]. As can be seen in Table 6, specimen SC1 reached the yielding point before specimen SC2. For instance, specimen SC1 yielded at 2.1% drift, which corresponded to a joint-bending moment of 671.8 kNm, while specimen SC2 yielded at 2.4% drift (a 15.8% increase compared to SC1), which corresponded to a joint-bending moment of 791 kNm (a 17.7% increase compared to SC1). In correlation with the yielding of the embedded steel profile, one can see that the yielding point of the specimen was at about the same load level of the yielding of the steel web panel in shear. As a result, the use of additional plates in the joint region improved the shear resistance, and thus, the joint resistance. After reaching the yielding point, the bending-resistance moment of both specimens kept increasing. Compared with the bending moment at the yielding point, the ultimate bending moment increased by about 14.4% in specimen SC1 and about 16.2% in specimen SC2. This ratio is an important response characteristic of the specimen and is called the specimen load sustainability. Furthermore, the ultimate bending moment of SC2 was 19.6% higher than that of SC1. At the yielding point, compared to the initial stiffness, the specimen SC1 lost about 36.7% stiffness at the yielding point and about 62.1% at the ultimate point. As for specimen SC2, these values were 39.5% and 65.9%, respectively. Note that the test ended at 5.5% drift. At this drift level, compared to the ultimate point, the bending-resistance moment decreased by 2.8% in specimen SC1 and 0.5% in specimen SC2,