Shaking Table Test for Seismic Response of Nuclear Power Plant on Non-Rock Site
Round 1
Reviewer 1 Report
In this study, shaking table tests were conducted to investigate the seismic responses of a safety-related nuclear structure with raft and pile group foundation at non-rock site under uni-directional and multi-directional seismic ground motions. The actual nuclear power structure was simplified to a three-story frame shear-wall structural model. The seismic ground motions were input in only one horizontal direction or three directions at the same time for the shaking table test. It was an interesting and practical study. However, the following suggestions should be addressed before possible publication.
1. Was the aspect ratio of the structural model approximated to that of the safety-related plant B?
2. The design drawings may be provided for better understanding of the baseplate connections and foundations of the two models.
3. Which direction of the three-directional earthquake records was shown in Fig. 5? Since the records from three directions of each acceleration station were used in the shaking table test, all the acceleration information should be provided.
4. In Table 1, why did the pile foundation model has larger natural frequency?
5. How were the vertical accelerations considered under the three-directional seismic excitations?
6. In the conclusion, it is recommended to use three-dimensional seismic motion input in the seismic response analysis of nuclear power plants in non-rock sites to make the results more reasonable. However, from the analysis results, it looks that the structural responses under the single and three directional ground motions were similar. The recommendation was not really practical.
Several sentences can be shortened or simplified.
Author Response
Thank you very much for your review comments. I have made corresponding revisions to the manuscript. Please refer to the submitted document for detailed information.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
This manuscript discusses a shaking table test conducted to analyze the seismic response of a safety-related nuclear structure on a non-rock site. Different foundation types (raft and pile group) and unidirectional/multidirectional seismic motions were examined. The results showed that the seismic response was affected by motion direction and foundation type. Simultaneous multidirectional input resulted in higher acceleration responses. Pile group foundations yielded smaller acceleration responses compared to raft foundations. The study suggests using three-dimensional seismic input for better analysis and enhancing the seismic performance of nuclear power plants with pile group foundations.
The authors honestly acknowledge that the scaled structure model used in the experiment approximates the experimental similarity relation with artificial mass and appropriate materials. However, due to the complex nature of soil and its disturbance in the shaking table test, then accurately simulating the soil-structure interaction is not feasible. Consequently, strict similarity relations cannot be established, and the study of soil-structure dynamic interaction is limited to qualitative analysis.
The authors provide sufficient detail on the experiment, and the obtained results appear reasonable and well-explained. The use of the Arias strong motion intensity index is reasonable, but it could be complemented with other intensity measures, such as Housner intensity or those more closely related to peak velocity of structural elements' motion.
Author Response
Thank you very much for your review comments. I have made corresponding revisions to the manuscript. Please refer to the submitted document for detailed information.
Author Response File: Author Response.pdf
Reviewer 3 Report
This is an interesting paper to read. However, it is unclear if this is a full research or rather a partial report since the subject presented would require much more details revealed to conclude about the novelty of the results. First of all, a model including reinforced concrete elements scaled 1:20 would require specially prepared concrete to preserve similitude laws. This problem is not properly explained in this paper. The scales of mass, model size and (perhaps) time scale should also be properly explained - see chapter 9 and appendix A of the book: Harris, Sabnis, Structural Modelling, and Experimental Techniques, CRC press, 1999. From this point of view this research is not enough well described.
Detailed problems. Some sentences are controversial or unclear:
Line 138: Quote: The law and characteristics of soil-structure dynamic interaction can only be studied qualitatively [21].
This sentence is not true and should be removed or modified
The English language is acceptable.
Author Response
Thank you very much for your review comments. I have made corresponding revisions to the manuscript. Please refer to the submitted document for detailed information.
Author Response File: Author Response.pdf
