Seismic Fragility Analysis of a High-Pier Bridge under Pulse-like Ground Motion, Based on a PCA and K-Means Approach
Round 1
Reviewer 1 Report
Dear authors,
Paper ID:
Seismic fragility analysis of high-pier bridge under pulse-like ground motion based on PCA and K-mean approach
I would like to thanks the authors and please consider the following comments:
1- The results need to be quantified so the comparisons would be noticeable for readers.
2- How did the authors verify the models in opensees?
3- The nonlinear response of the piers how can be verified?
4- What are the innovatively of the novel seismic fragility analysis approach used in manuscript?
5- How are the measure of damage states? (Used in the plots)
6- The quality of pictures and plot need to be improved.
Minor editing of English language required, Please reconsider the manuscript so with fluent English for readers.
Author Response
Please see the attachment.
Author Response File: 
Author Response.docx
Reviewer 2 Report
The article concerns a novel approach in research of a seismic fragility of high-pier bridges, which is important from the point of view of their resistance to seismic phenomena. The authors conducted a number of tests on scale models of buildings of various constructions made of balsa. The authors consider a crucial problem in terms of safety, hence it will be interesting and useful for many researchers. The article is extensive and its structure is correct. The abstract contains all the necessary information presented in an essential form. The introduction references a sufficient number of sources (some remarks below), mostly from recent years, as well as a few older articles. The originality and novelty of the research is correctly exposed. Further on, the authors presented the background of their considerations, assumptions for the research and all necessary information on the methods applied. Later in the manuscript, the authors presented the results of the research. The presentation of the results is clear. The authors correctly analyzed the results. The approach and the results presented in the study look credible. The work ends with accurate conclusions of significant value. The paper has been prepared very carefully, and certainly is worth to be published in Applied Sciences after a revision described below.
The language used in the work is correct. There are no problems with understanding the intentions of the authors.
Detailed remarks:
Wrong section numbering - Background should be no. 1 and then consecutive 2, 3 and so on.
Wrong references numbering - it should be just 1, 2, 3 and so on, no Roman numerals can be used here
Considered bridge - it would be useful to comment whether it is based on a real object, or is it a structure based on random dimensions and other parameters. Such information could be of interest to some researchers.
The colored numbers in Figures 8 and 10 are hard to read.
Author Response
Please see the attachment.
Author Response File: Author Response.docx
Reviewer 3 Report
It is a nice and interesting manuscript, there are some suggestions to improve the quality of this study. There is no line numbering which makes revision difficult.
1. What are the 91 pulsatile ground motions mentioned in the manuscript.
2. How did the authors select the 9 accelerations shown in Table 1 and how do they relate to the previous 91?
3. In figure 2 we can see the response spectra of acceleration 100, but I can understand why there is this variation as we cannot see the different spectra. At least the 9 presented in the Table.
4. IMS why is it presented with difficulty in paragraph 3? It is not mentioned in the abstract or introduction. Readers were confused. Please modify it in order to make this study more smoothly presented.
5. The quality of the figures should be improved.
6. The mathematical approach must be clarified and the conclusions re-clarified
Finally, I would recommend checking the text again.
I would recommend checking the text again.
Author Response
Please see the attachment.
Author Response File: Author Response.docx
Reviewer 4 Report
Dear authors,
The paper presents several methods to understand the damage on a bridge due to pulse-like ground motions of earthquakes. It is very interesting and the topic is relevant to be published in Applied Sciences Journal.
However, I have several comments and suggestions listed below.
The structure of the paper is very confusing and difficult to follow. Please reformulate the manuscript according to the MDPI layout:
1. Introduction
2. Background/ literature review (optional: this is not mandatory, but some authors include this extra section)
3. Methodology
4. Results and discussion (can be separated)
5. Conclusions
The abstract looks quite long; please keep the abstract under 200 words, as the Journal layout suggests.
The authors should follow the MDPI Applied Sciences’ layout for the citations and list of references. In this text is presented “example[I,ii]” instead of “example [1,2]”.
Please indicate the meaning of PEER.
The 9 case studies presented in Table 1 should have more citations, including the data. Why these 9 earthquakes were selected; was it because it was recorded pulse-like ground motions? The 9 case studies presented in Table 1 should have more citations, including the data. Why these 9 earthquakes were selected; was it because it was recorded pulse-like ground motions? Please explain in more detail each event.
There are many publications related to the 1995 Kobe earthquake that should be cited. The magnitude of 6.9 was not significant to cause the tremendous observed damage; we now know that due to local Geology and topographic features, the seismic waves were trapped and for that reason, they amplified. After the Kobe earthquake, Japan approved a new code for earthquake-resistant construction. The earthquake also caused many fires in the city, and due to that, fire safety regulations were also updated.
It is not clear if Figures 1 and 2 were obtained from previous studies, or if the calculations were carried out by the authors. Please clarify; if these are results, then the figures should be moved to the Results section.
Why is the unit of the bridge in Figure 3 in cm? Please use meters. Why was this bridge selected? Is this a real bridge, or a standard model?
Please clarify Figure 6: What do you mean by “wide distribution”? In the text, the authors refer to IMS, while the plot shows PGA. The authors also say: “Notably, the correlation coefficient values between PGV and Vp, as well as Arms and aRMS, are both 1.0, indicating that these IMs are completely correlated.” But I don’t understand how the authors pick up this result from Fig 6.
Please indicate the reference of Pearson (1901) and Hotelling (1933)
The authors used PCA analysis. However, I did not find those results: please indicate the PCS, the eigenvalues, and their percentages of explanation. As mentioned above, the paper is very difficult to follow due to the organization of the sections. Are the results of PCA presented in Figure 11? Still, the authors should describe what are F1, F2 and F3 components.
The authors also use Cluster analysis, but again the methodology and results are presented in a very confusing way. Please clarify. The clusters (groups) obtained in Figures 12 and 13 should be explained in more detail, including what is the meaning of the classes related to the PCA; In Figure 13, 1st and 2nd PCA should be presented as F1 and F2?
Legend of Fragility curves (Figs 14 to 17) should be larger; I cannot read them.
How did the selected bridge perform in terms of damage probability? Can you tell which pier could be more affected? Would the bridge collapse? Would it have some minor or moderate damage? Do you have any suggestions to improve the safety and reinforcement of the bridge related to earthquakes?
Author Response
Please see the attachment.
Author Response File: Author Response.docx
Round 2
Reviewer 3 Report
Author Response
The authors would like to thank sincerely the reviewer again for his/her instructive comments that improved the quality of this paper significantly. And the revised article are as follows, please check it.
Reviewer 4 Report
Dear authors,
I appreciate the efforts to reply to comments; however, the manuscript did not improve significantly.
Author Response
The authors would like to thank sincerely the reviewer again for his/her instructive comments that improved the quality of this paper significantly. And the revised article are as follows, please check it.
