## 6 Conclusions  
This study aimed to investigate the dynamic behavior and structural safety of a commonly used vertical hydrogen storage vessel under seismic conditions through shaking table testing. To achieve this, an actual site survey was conducted to select the target structure, and the design of the test specimen for the shaking table test was validated through analytical methods. Subsequently, the specimen was fabricated, and a seismic simulation test was conducted on the shaking table. The following conclusions were drawn based on the results of the study:  
* Based on the response acceleration of the target structure to the artificial earthquake generated according to the seismic design criteria and analyzed on a time-history basis, it was observed that the seismic motion was amplified by a factor of approximately 10 compared to the original load magnitude. Consequently, it is inferred that the seismic motion occurring during an earthquake could cause significant damage to both the internal and external aspects of the structure, depending on the structure's form and the composition of materials.
* In the analytical verification, the response acceleration tended to decrease as it was transmitted to the point where the weight center of the target structure was located. However, in the actual shaking table test, there was an opposite trend in the acceleration response. This phenomenon is attributed to the slushing effect caused by the seismic motion as the weight of hydrogen is replaced with water. It is considered that additional research on materials that can replace the weight of hydrogen will be necessary in the future.
* The test specimen, a vertical hydrogen storage vessel, was interpreted and experimentally verified to have no structural integrity issues with the main body and anchor in the event of an earthquake. However, the current installation method on protrusion concrete for hydrogen utilization poses a structural risk as a vulnerability when external forces such as earthquakes are applied.
* The failure mode of the test specimen during the shaking table test was similar to the analytical verification results where concrete along the boundary of the support and foundation was damaged due to concentrated settlement stress. In both actual damage cases and analytical verification results under external and seismic loads, concrete fractured along the boundary of the support and foundation, and the concrete at the foundation was completely separated. Therefore, it is recommended to explore alternative approaches considering on-site installation conditions, such as by producing the protrusion concrete element with reinforced concrete or adjusting the height of the foundation concrete to directly install the structure onto the foundation.  
Figure 18: The Von Mises stress response results of the supporting column.  
**Author Contributions:** Conceptualization, W.J.; Software, S.L.; Validation, S.L.; Investigation, B.J.; Writing--original draft, S.L.; Writing--review & editing, W.J. All authors have read and agreed to the published version of the manuscript.  
**Funding:** This research was supported by the \"Regional Innovation Strategy (RIS) and Basic Science Research Program\" through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (MOE) (2022 RIS-005 and 2021R1A6A1A03044326).  
**Institutional Review Board Statement:** Not applicable.  
**Informed Consent Statement:** Not applicable.  
**Data Availability Statement:** Data are contained within the article.  
**Conflicts of Interest:** The authors declare no conflict of interest.