## 5 Conclusions  
This study focused on the dynamic behavior of the Replaceable Steel Link (RSL) system, intended to serve as a structural fuse. Cyclic loading tests were carried out on the RSL system at sliding slot lengths, a key variable affecting its performance. The experiments assessed the behavior of reinforced concrete columns retrofitted with RSLs under realistic seismic loads. Torsional effects, reflecting the eccentricity of lateral forces, were also taken into account. In essence, this study contributes to the understanding of the versatility and adaptability of the RSL system in seismic design, specifically in its role as a replaceable structural fuse under torsional load. It builds upon and extends the findings of previous research. The primary conclusions drawn from the study are as follows:  
1. The RSL system exhibited significant control over crack propagation in reinforced concrete columns. Initial flexural cracks were observed at a drift ratio of 0.75% in all specimens. Under eccentric loading, specimens with a 5 mm sliding slot length showed shear cracks at a drift ratio of 1.75%. In comparison, specimens with a 10 mm sliding slot length exhibited shear cracks at a drift ratio of 1%. These findings  
\begin{table}
\begin{tabular}{c c c c c c} \hline \multirow{2}{*}{**Drift Ratio** **(\%)**} & \multicolumn{4}{c}{**Cumulative Energy Dissipation Capacity (kN\(\cdot\)mm)**} \\ \cline{2-6}  & **NE-10** & **E130-10** & **NE-5** & **E65-5** & **E130-5** \\ \hline
0.2 & 10.8 & 10.9 & 9.0 & 14.6 & 13.4 \\ \hline
0.25 & 23.8 & 26.5 & 22.2 & 33.1 & 33.9 \\ \hline  
indicate that the sliding slot length plays a crucial role in crack propagation. After the experiment concluded, the damaged steel link could be easily replaced, thus confirming the feasibility of using the RSL system as a structural fuse. 2. The maximum load capacities exhibited variations based on sliding slot length and eccentric distance. An increase in eccentric distance resulted in a 70 to 80% change in maximum load capacity, while the variation in maximum load due to sliding slot length at the same drift ratio was around 10%. This finding underscores the RSL system's capability to effectively resist torsion. Specimens with a 5 mm slot reached their yield strain earlier and showed a higher strain compared to those with a 10 mm slot. This result was in line with the initial design expectations, demonstrating that adjustment of the sliding slot length can be an effective method to regulate the yielding behavior of a steel link. 3. The study analyzed torsional moments and twist angles at various drift ratios, notably at the onset of major cracks. In all specimens, there was only a minimal difference in torsional moment and twist angle at the conclusion of the experiment compared to the measurements just before reaching the final drift ratio. This outcome suggests that retrofitting reinforced concrete columns with the RSL system can effectively prevent brittle failure due to torsion. 4. The difference in cumulative energy dissipation due to variations in sliding slot length was marginal, ranging from 1 to 4%. However, with an increase in sliding slot length, the difference in cumulative energy dissipation attributable to augmented eccentric distances reached approximately 50%. This indicates a notable impact of sliding slot length on the system's ability to resist torsion. Consequently, it is recommended that the length of the sliding slot be based on the specific seismic design objectives when employing the RSL system as a structural fuse. 5. This study investigated the behavior of reinforced concrete columns retrofitted with the RSL system under torsional loads, highlighting the system's potential as a structural fuse. Despite this, the complexity inherent in analyzing structural fuse systems like the RSL is well recognized. Therefore, further research should be conducted to develop analysis methods for RSL systems.