Restoring Force Model of Precast Segmental Reinforced Concrete Piers after Seawater Freeze–Thaw Cycles
Round 1
Reviewer 1 Report
The study entitled " Restoring force model of precast segmental reinforced concrete piers after seawater freeze-thaw cycles" deals with investigation of the behavior of concrete against different cycles of seawater freeze-thaw. Various parameters such as the axial compression ratio, the diameter of the longitudinal reinforcements and the stirrup distance, and etc. were considered as variables, and the effects of each of them on the response of the sample under low dynamic loads were studied and finally, restoring force model of RC piers was determined using regression analysis from laboratory data. In my opinion, the authors have made a good work here, but the results are not well interpreted and presented, number of figures and tables are not sufficient to understand the outcomes of the study. Before advising a major revision for the manuscript, there are a few typographic errors I want to mention, and several questions to be answered.
1. In the abstract, the strength of the current research compared to other researchers is not clearly defined.
2. The abstract should be supported by some quantitative findings.
3. Please add a paragraph about effect of freeze-thaw cycles on the civil projects such as concrete, geomaterials and etc. Some recent papers should be cited in the introduction part, such as 10.1155/2013/650791, 10.1061/(ASCE)MT.1943-5533.0003905, 10.13168/AGG.2021.0005
4. At the end of the Introduction, where the author introduces the main claim of his research (restoring force model of precast segmental reinforced concrete) or reasserts this claim, the paper should be including a paragraph to explain the importance of the subject, novelty and originality of the paper.
5. The legends of some Figures (e.g. Figure 5) do not indicate a specific parameter. More care has been taken in choosing the caption of the figure so that it expresses the graph and the variable used in it.
6. Please present more details about sample preparation.
7. The interpretation of the results is poor. Discussing the results can make the paper more attractive.
8. The results should be compared with previous research. There seems to be a difference with previous research. Reasons for disagreement should be stated.
9. Add a discussion section to the article. In this part, after summarizing your key findings, you should compare your results with previous studies.
Author Response
The authors are very thankful to the reviewer for many useful and valuable comments and suggestions, which we believe have strengthened the quality of the manuscript. We have addressed the points raised by the reviewer, and accordingly revised the manuscript (changes are highlighted in red color).
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Overall the paper is very thorough, I suggest acceptance of the paper after some minor changes.
Kindly improve the abstract by adding the results' actual numbers, percentages.
Improve the language (in results section)
Clarify the research significance section.
Number of literature present in the section is not up-to-date.
revise the Figure 13 and 14 by enlarging it, so the readers can read it easily.
The points in conclusion section is a bit lengthy. Shorten these points by dividing it to more smaller points.
Author Response
The authors are very thankful to the reviewer for many useful and valuable comments and suggestions, which we believe have strengthened the quality of the manuscript. We have addressed the points raised by the reviewer, and accordingly revised the manuscript (changes are highlighted in red color).
Author Response File: 
Author Response.docx
Reviewer 3 Report
Article Type: Research Paper
The manuscript presents results of an extended experimental study. 12 precast segmental concrete piers with different numbers of seawater freeze-thaw cycles, axial compression ratios, longitudinal reinforcement diameters, and stirrup spacing was constructed and tested under low cycling loading and at different axial compression ratios and after 0, 25, 50, 75, 100, and 125 freeze-thaw cycles in natural seawater. The hysterical characteristics of pre-cast segmental RC pies were analysed, and the restoring force model of RC piers considering the seawater freeze-thaw damage and design parameters were established.
In general, the paper is extremely well written, the results are clearly presented, and the conclusions are supported by the results. The correlation between the analytical and the experimental results is quite good. The introduction is quite complete, and the problem is well established. In the opinion of this Reviewer this study is worthy of publication after minor revision and is very useful for scientific research. However, this Reviewer has some recommendations and questions, as described below:
· Section 2.1, line 159: You probably want to write “In Table 1”. Please correct it.
· Section 2.1, Table 1: You should include in the first line of Table 1 the symbol letters of the axial compression ratio, the longitudinal reinforcement diameter and the stirrup spacing.
· Section 2.1, page 6: A picture with the used connectors should be included.
· Section 2.2, line 192: What do you mean with ordinary reinforcement. Please give more details.
· In lines 194 – 197 you mention that the ultimate tensile strength and the ultimate strain of the rebar connected with the rebar connector decreased by 8% and 52%, respectively. Is it correct according to Figure 5?
· Section 2.3: The expressions (1) and (2) are wrong.
· Section 2.5, line 372: The assembly is not finished in Figure 12f. The third part of assembling is missing. How did you connect the after-cast segment with the freeze-thaw segment. A picture is needed.
· Section 3.2, line 432: A capital letter is needed.
· Section 3.2: In lines 461-462 you mentioned that “As the seawater freeze-thaw cycles increases, the spalling height of pier concrete decreases gradually after the low cyclic load test.” Is there any logical explanation for this? According to section 2.4 somebody should probably expect the opposite.
· Section 3.3: A table with the experimental results should be included in this section. It could be helpful for the reader.
· Section 3.3, line 505: You probably mean Figure 19 (g-j) and not Figure 20 (g-j). Pleas correct it.
· Section 4.1: In expression 10 what does λ parameter mean?
· Section 4.3, lines 664 – 676: Please correct the numbering of the referred equations and path 9-10 (13-14) in line 673.
· Table 5: Please check the numbers in the last row.
Author Response
The authors are very thankful to the reviewer for many useful and valuable comments and suggestions, which we believe have strengthened the quality of the manuscript. We have addressed the points raised by the reviewer, and accordingly revised the manuscript (changes are highlighted in red color).
Author Response File: Author Response.docx
Round 2
Reviewer 1 Report
The manuscript is accepted in its current form.
