PONE-D-24-42244Axial compression behavior and failure mechanism of CFRP-confined circular hollow steel tube short columns: theoretical and numerical analysisPLOS ONE

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Address all reviewer comments, particularly emphasizing the novelty and contribution of your work.

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Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Partly

Reviewer #2: Partly

Reviewer #3: Partly

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2. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: No

Reviewer #2: I Don't Know

Reviewer #3: Yes

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3. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: No

Reviewer #2: Yes

Reviewer #3: No

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4. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: Yes

Reviewer #2: No

Reviewer #3: Yes

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5. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: This paper presents a study that combines theoretical research with numerical analysis to evaluate the effectiveness of CFRP reinforcement in CHST short columns under axial compression. New formulas for calculating the yield and ultimate bearing capacities of CFRP-CHST short columns are proposed and validated through comparisons with experimental results and finite element analysis. It is essential to highlight the main contributions of this research while clearly differentiating the work conducted by others from the new insights presented in this study. The following issues need to be addressed for clarification.

- Acronyms and abbreviations need to be defined when they are mentioned for the first time. Acronyms are used in many locations without definition. Symbols are used without definition. Please add a list for the symbols used.

- Please include an illustration for cross-sectional information (D, d, ts, and L) in Fig 1.

- On page 12, the authors summarized the specimens tested by Haedir and Zhao [18], but they did not provide any information about the specimens used in the experiments conducted by Teng and Hu [23]. A Comprehensive Table Considering All Specimens Should Be Included. Additionally, Tables 4 and 5 do not include comparisons of the specimens tested by Teng and Hu [23].

- It is imperative to include the specified parameters and to provide a clear rationale for their selection, along with a detailed explanation of their anticipated impact on the behavior of circular CFRP-CHST short columns. This will significantly enhance understanding. The parametric study must encompass a comprehensive range of parameters to thoroughly examine their effects on theoretical formula of the yield and ultimate bearing capacities of CFRP-CHST short columns.

- How interaction between the steel and CFRP was modelled?

- Line 240-241, “the two loading plates at the ends are modeled as analytical rigid bodies”. Please explain in the manuscript.

- The study only considers CFRP-CHST short columns under axial compression, not addressing other loading conditions such as flexure or cyclic loading. Mention the limitations regarding loading conditions explicitly and propose future studies to include other loading conditions. Highlight the potential impact of these conditions on the behavior of CFRP-CHST short columns.

- The study is focused on circular CFRP-CHST columns, limiting the generalizability of the conclusions to non-circular cross-sections. Acknowledge this limitation and suggest extending the study to non-circular cross-sections. Discuss how the two formulas might differ for other geometries and propose a methodology for investigating these cases.

- More discussion about the effect of CFRP effect with higher slenderness ratios is required.

- The references cited are largely irrelevant to the research topic, especially references from [1] to [10]. It is crucial that these references be updated to include more recent and pertinent sources that directly relate to the subject matter.

Reviewer #2: From my perspective, this paper is highly repetitive and lacks novelty. The results presented are merely reiterations of existing findings that have been previously collected, analyzed, and modeled by our team through both numerical and machine learning approaches. Unfortunately, there is no significant new contribution in this study. Extensive literature already covers similar numerical and theoretical work on these types of specimens, and existing models adequately address stress-strain relationships for these materials. Given this context, I do not believe this paper meets the standards for publication in any scholarly journal.

Reviewer #3: Title of Paper: Axial compression behavior and failure mechanism of CFRP-confined circular hollow steel tube short columns

Manuscript Number: PONE-D-24-42244

This manuscript has taken CFRP-CHST short columns into consideration and studied the structural behaviour of such columns under axial compression. The study is well organized and the authors tried to investigate the concept of their study through different methods. While the novelty of the study is a bit poor, the package of the whole study is considerable from my point of view. However, it needs some amendments to fulfill the requirements of publishing in the journal.

Comments

1. Lines 106-109: This part needs to be polished in terms of language.

2. Fig. 2: The stress distribution is shown separately for the steel tube and the CFRP. Since I have seen this type of illustration a lot, I suggest showing the stress distribution on a section of CFRP-CHST. Can you do it?

3. For the equations you need to clarify each parameter beneath the formula.

4. Equations 5 and 18: It seems the authors just considered the area of steel. What about the impact of carbon fiber reinforced polymer? Has been ignored?!

5. Line 136: What is assumption 2? Please explain.

6. Lines 124, 126, 168: The terms of bearing capacity, yield bearing capacity, ultimate bearing capacity were used and the final equations 5, 18, 22 are a bit confusing! You can provide and highlight a final formula as the outcome of this study. I think would be user-friendly.

7. Equations 5, 18, 22: Still, I could not recognize the area of CFRP in these equations. Please clarify.

8. Table 1: What are nl , nh ?

9. Table 2: I think it is unnecessary as the necessary details of CFRP are already mentioned in Section 3.1.

10. Line 253 needs a space.

11. Fig 4: needs some adjustments. One arrow is missing and b) overlaps with the column.

12. Table 3: The information here can be written within the manuscript and there is no need for a single-row Table here!

13. I think there is no need for 3 sub-sections for Section. 3 as all of the subsections are very short.

14. Line 292: Do you mean Yield?

15. Line 301: “Comparison of longitudinal displacement at yield for CHST short columns”, at yield level/point.

16. Table 5: It needs a footnote explaining the parameters.

17. Conclusion Line 6: “A theoretical formula “, please highlight which one.

18. Conclusion No. 3: How this is concluded? From FEA?

19. I suggest to re-write the conclusions with specific details. The conclusion looks broad and not only for this study.

20. Line 25: In the submission process, it is mentioned that the data is available within the manuscript and supplementary information, and the statement “Data will be made available on request” contradicts this.

21. The references are very limited and almost 10 of 23 are outdated. It is usually suggested to reference articles older than ten years for only 10 percent of the total citations.

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Reviewer #1: No

Reviewer #2: No

Reviewer #3: Yes:  Payam Sarir

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Axial compression behavior and failure mechanism of CFRP-confined circular hollow steel tube short columns: theoretical and numerical analysis

PONE-D-24-42244R1

Dear Dr. Hairong Huang,

We’re pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it meets all outstanding technical requirements.

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Mohammadreza Vafaei, Ph.D.

Academic Editor

PLOS ONE

Additional Editor Comments (optional):

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. If the authors have adequately addressed your comments raised in a previous round of review and you feel that this manuscript is now acceptable for publication, you may indicate that here to bypass the “Comments to the Author” section, enter your conflict of interest statement in the “Confidential to Editor” section, and submit your "Accept" recommendation.

Reviewer #1: All comments have been addressed

Reviewer #3: All comments have been addressed

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2. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Yes

Reviewer #3: Yes

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3. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: Yes

Reviewer #3: Yes

**********

4. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: Yes

Reviewer #3: Yes

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5. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: Yes

Reviewer #3: Yes

**********

6. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: The authors have responded well. The revised manuscript can be considered for an acceptance in journal

Reviewer #3: Dear authors,

Thank you for addressing all the comments and consider the details in revising the manuscript.

All the best.

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7. PLOS authors have the option to publish the peer review history of their article (what does this mean? ). If published, this will include your full peer review and any attached files.

If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy .

Reviewer #1: Yes:  Asmaa Y Hamed

Reviewer #3: Yes:  Payam Sarir

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