Local Scour Reduction around Cylindrical Piers Using Permeable Collars in Clear Water

Round 1

Reviewer 1 Report

This manuscript proposed a new form of permeable collar and investigated the local scour reduction effect by experiments. The topic is worthy of research and the coclusions are supprtted by the resutls. Some comments should be considered when the authors revise this manuscript.

1. Some new publicated papers should be added;

2. In this paper, the influences of the porosity, installation height, diameter, and thickness of permeable collars on local scour reduction in clear water were studied. However, some useful suggestions should be presented for engineers, for exemple, new equations like (1) and (2)?

3. The conclusion (5) is just an additional remarks, not new findings. 

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

Congratulations to the authors of a very interesting article. I have two content requests:

1. Please describe in more detail the material used for research (ingredients, structure, properties)

2. Did the research take into account the costs of possible use? If so, please provide cost analysis.

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

This manuscript investigates the local scour reduction around bridge piers by applying permeable collars. This manuscript basically presents experimental results. It has some shortcomings, which are presented in the following:

1.      Title: Is it “Around Cylindrical Pier Using Permeable Collar” or “Around Cylindrical Piers Using Permeable Collars”?

2.      Line 10: Why did you use “the” in “around the cylindrical piers”? Which piers do you refer to? I suggest using “around cylindrical piers”.

3.      Line 17: What do you mean by “the reduction effect is the best”?

4.      Line 19: What do you mean by “the protective effect is the best”?

5.      Lines 19-20: What do you mean by “which is consistent with that of the solid collar”?

6.      How can the results of your experimental-based study “provide a reference for local scour reduction of bridge piers”?

7.      General comment: The novelty of the study should be clearly mentioned in the abstract and introduction.

8.      Line 26: Instead of “bridge engineering”, use “bridge piers”. Also, add “scour depth”.

9.      Lines 29-43: Shorten this paragraph.

10.  Lines 44-45: Describe what you mean by “the passive measurements and the active measurements” here.

11.  Figure 1: Add more description to the text for this figure. Only one sentence is not enough to describe this figure, which has 8 different parts.

12.  Line 58 and Line 64: Since you did not use Eq. 1 and Eq. 2 in your work, I suggest removing these equations from the introduction as they make it too focused rather than an appropriate introduction to the topic of your study.

13.  Introduction: This section is weak and should be improved by adding the problem statement and the importance of the topic.

14.  Introduction: The literature review presented in the manuscript is very little and selective, while there are many studies conducted on the topic (check 10.1007/s40996-018-0129-9 for example). The authors are advised to present a comprehensive literature review in a bid to show the gap in the literature.

15.   Line 62: Reference 12 is a master thesis and Reference 11 is a PhD thesis. I suggest removing them.

16.  Lines 85-93: The novelty of the work should be clearly stated in the introduction.

17.  Line 87: This sentence requires a proper reference.

18.  Lines 121-134: This paragraph does not belong to this subsection, i.e., Experimental Setup. So, it should be moved to its correct place.

19.  Line 139: This phrase “According to the previous research results” requires a reference.

20.  Line 194: I suggest adding the relationship of Pearson’s correlation coefficient as you used it in the results and discussion.

21.  Line 195: I suggest separating the results and discussion into two sections.

22.  Tables 3-5: I suggest merging these tables into one table.

23.  Discussion: Improve this section by explaining how your scaled experimental results can be useful in practice.

24.  Reference: This section indicates that the literature review is weak. Also, remove the outdated reference (like references 8 and 13).

Author Response

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Author Response File: Author Response.pdf

Round 2

Reviewer 3 Report

This manuscript has been improved significantly. Nonetheless, it has some minor shortcomings, which are presented in the following:

1.      Lines 10-13: This sentence becomes too long in the revision. Divide it into at least two sentences.

2.      Line 10: Why did you use “the” in “the shortcomings of the solid collar”? Which shortcomings and which solid collar do you refer to?

3.      Abstract: I suggest adding the number of experiments done in this study to the abstract.

4.      Lines 22-23: Is it “close to that when” or “close to when”?

5.      Line 23: What do you mean by “installed on the surface of the sediment”?

6.      Lines 27-28: How can the results of your experimental-based study “provide a reference for local scour reduction of bridge piers” (from the previous round the review)? I suggest changing “The research results can provide a reference for local scour reduction of bridge piers” to “The results can give a perspective on the reduction of local scour depths around bridge piers.”

7.      General comment: The novelty of the study should be revised in the abstract (from the previous round the review).

8.      Line 26: Change “local scour depth” with “scour depth” because it is more general.

9.      Line 139: This phrase “According to the previous research results” requires a reference.

10.  Line 478: In this line, it is stated that “The reduction efficiency of the permeable collar is negatively correlated with its thickness.” I suggest adding the relationship of Pearson’s correlation coefficient and calculate it to quantify this correlation.

11.  Lines 314-317: This should be moved to the end of “materials and methods” as it is not one of the results of your study.

12.  Tables 2-5: These tables show the maximum scour depth around bridge piers in your experiment for different parameters. For instance, Table 2 presents the maximum local scour depth around the pier using a permeable collar with different porosity. The question is what are installation heights, diameters, and thicknesses of permeable collar for these results? I understand that Table 1 tries to give a summary of different conditions of experiments. Nevertheless, I suggest adding the values of constant parameters to the captions of Tables 2-5 to avoid misunderstanding.

13.  Data: I suggest providing data as an appendix because it will provide a good opportunity for future readers to use the data for comparison purposes.

Author Response

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Author Response File: Author Response.pdf