## 4 Experimental Results and Analysis
### Energy Dissipation  
The energy dissipation characteristics of a member are an important measure of its seismic performance. The energy dissipation in each cycle was calculated from the enclosed area within the hysteresis loop for each cycle. The cumulative energy dissipation was computed by summing the energy dissipated in previous cycles. Figure 13 presents the definition of the dissipated energy of one hysteresis loop and the maximum dissipated energy that could be theoretically dissipated within the same load and displacement limits, assuming a perfectly plastic response. The dissipated energy is illustrated as the black solid hatched area. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Pull** & **SC1** & **SC2** & **Push** & **SC1** & **SC2** \\ \hline
**Drift (\%)** & **Stiffness Degradation (\%)** & **Drift (\%)** & **Stiffness Degradation (\%)** \\ \hline
0.25 & 100 & 100 & \(-\)0.25 & 100 & 100 \\
0.5 & 94.12 & 92.44 & \(-\)0.5 & 94.03 & 92.43 \\
0.75 & 88.11 & 86 & \(-\)0.75 & 88.03 & 87.27 \\
1 & 80.94 & 81.77 & \(-\)1 & 82.24 & 82.61 \\
1.25 & 75.88 & 76.80 & \(-\)1.25 & 77.27 & 78.18 \\
1.5 & 72.09 & 72.19 & \(-\)1.5 & 73.09 & 74.13 \\
1.75 & 68.76 & 69.45 & \(-\)1.75 & 70.10 & 70.33 \\
2 & 64.56 & 66.36 & \(-\)2 & 65.81 & 66.44 \\
2.25 & 59.91 & 62.80 & \(-\)2.25 & 60.92 & 63.09 \\
2.5 & 55.39 & 59.29 & \(-\)2.5 & 56.82 & 60.01 \\
3 & 48.17 & 52.75 & \(-\)3 & 48.58 & 53.49 \\
3.5 & 41.98 & 46.96 & \(-\)3.5 & 42.83 & 47.37 \\
4 & 37.55 & 41.75 & \(-\)4 & 38.15 & 42.16 \\
4.5 & 33.07 & 37.42 & \(-\)4.5 & 33.64 & 37.99 \\
5 & 29.61 & 33.82 & \(-\)5 & 30.14 & 34.41 \\
5.5 & 26.73 & 30.66 & \(-\)5.5 & 26.82 & 31.09 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Joint-stiffness degradation. Figure 12: Stiffness degradation ratio. Figure 13(a) presents the cumulated dissipated energy at each drift level, including the total cumulated dissipated energy. Figure 13(b) shows the energy dissipation ratio at each displacement level where two loading cycles were performed. For the drift levels under 2%, the dissipated energy slowly increased with respect to the loading cycle. However, the dissipated energy ratio was smaller than 10%, which shows there was a linear relationship between the drift and the joint-bending moment. During step 2, from 2% to 4% drift, the dissipated energy quickly increased. This can be explained by the fact that the yielding points in steel in step 1 became the yielding regions in step 2, where the energy dissipated during cyclic loading. During loading step 2, the dissipated energy of specimen SC1 was 4.8% greater than specimen SC2. As for loading step 3, the dissipated energy increased for both specimens but was 9.5% more for specimen SC2. According to Figure 11, the embedded steel profile of SC1 yielded at 1-2% drift, therefore, from 2-4% drift, the yielded region propagation resulted in the high energy dissipation ratio. The embedded steel profile of SC2 yielded at 1.5-4% drift. Thus, after 4% drift, the yielded region was still able to propagate, resulting in the high energy dissipation ratio during loading step 3. As can be seen from Figure 13(b), from the beginning to the end of the test, the energy dissipation ratio of SC1 was greater than SC2. This was due to the steel yielding taking place earlier in SC1 than in SC2. Therefore, after 4% drift, the energy dissipation ratio of SC1 slowly increased, while that of SC2 quickly increased. At the end of the test (5.5% drift), the energy dissipation ratio of SC2 tended toward that of SC1. Figure 15 and Table 5 present the cumulative energy dissipation of the two specimens, SC1 and SC2. One can observe that between both specimens, there was almost no difference. As expected, the energy dissipation was small when the drift was smaller than 2% and quickly increased at higher drifts. At  
Figure 14: Energy dissipation for each cycle. Figure 13: Definition of energy dissipation. the end of the test, the total cumulative energy dissipation in SC2 was 3.5% more compared to SC1.