Shear Resistance Assessment of the Y-Type Perfobond Rib Shear Connector under Repeated Loadings
Round 1
Reviewer 1 Report
This article is very interesting for a choosen group of users. Overall, the paper is nicely written and present good results. The following item are to be addressed before the manuscript can be published:
Fig. 6 and 8 - the results will be clearer if they are presented in colors.
Author Response
Reviewer #1
The authors appreciate your thoughtful comments and constructive suggestions, which are very helpful in improving the grammatical and technical quality of the paper. Your work is greatly appreciated. A complete revision of the manuscript has been performed according to your comments and suggestions. We hope that you are satisfied with them. If you have any questions or suggestions, please let us know and we will happy to make further improvements. The detailed responses to your comments are shown below:
Point 1
Fig. 6 and 8 – the results will be clearer if they are presented in colors.
Response
The authors have changed the line types in figures with various colors. (Figure 6 and 8)
Author Response File: 
Author Response.docx
Reviewer 2 Report
Some suggestions for improvement:
(i) page 1 line 19: Should mention that the connector is used in composite steel-concrete structures
(ii) page1, line 15: add composite steel-concrete keyword
(iii) page 2, lines 89, 90 and 91: Remove the data in parenthesis because they are already shown in table 1
(iv) page 3: add more explanatory drawing to figure 1, such as the detail of the connector shown in figure 3 and figure (1) of table 1 on bibliographic reference 12.
(v) the formula (4), page 41, depends on the value of fck. However they only test for fck=60 MPa. They should explain the influence of fck on formula (4).
(vi) page (14), line 265 "In table 12" must be removed because it is already mentioned in previous sentence.
Author Response
Reviewer #2
The authors appreciate your thoughtful comments and constructive suggestions, which are very helpful in improving the grammatical and technical quality of the paper. Your work is greatly appreciated. A complete revision of the manuscript has been performed according to your comments and suggestions. We hope that you are satisfied with them. If you have any questions or suggestions, please let us know and we will happy to make further improvements. The detailed responses to your comments are shown below:
Point 1
Page 1, line 19: Should mention that the connector is used in composite steel-concrete structures.
Response
In abstract and introduction, the more descriptions about steel-concrete composite structures and use of shear connectors were added as follows: “The steel-concrete composite structures consist of two different material parts, which are connected with reliable shear connectors to enable the combined action of the steel and concrete members. The shear connectors may experience either one-directional repeated cyclic loadings or fully reversed cyclic loadings depending on the structural functions and acting loadings.”
Point 2
Page 1, line 15: Add composite steel-concrete keyword
Response
“steel-concrete composite structure” was added as a keyword.
Point 3
Page 2, lines 89, 90 and 91: Remove the data in parenthesis because they are already shown in Table 1.
Response
It has been modified. Lines 92-94 in the revised article.
Point 4
Page 3: Add more explanatory drawing to Figure 1, such as the detail of the connector shown in Figure 3 and Figure 1 on bibliographic reference 12.
Response
We have revised Figure 1. The specific descriptions and 3D image are added. Additionally, the drawing type in Figure 3 was changed to the same type of Figure 1.
Point 5
The formula 4, page 41: depends on the value of fck. However, they only test for fck=60MPa. They should explain the influence of fck on formula 4.
Response
The formula 4 has been proposed based on experimental results from various design variables as well as concrete strengths (30 to 60MPa). Kim et al. (2021) performed additional push-out tests with high-strength concrete (60MPa) to investigate the effect of concrete strength, in addition to the previous experimental results [Ref. 15, 16, 17, 18] with the concrete strengths ranging from 30 to 50MPa.
Point 6
Page 14, line 265: “In Table 12” must be removed because it is already mentioned in previous sentence.
Response
We have deleted some of the repeated expressions of “In Table 12”.
Author Response File: Author Response.docx
Reviewer 3 Report
- General comment
In my opinion, the topic of the article is interesting and relevant for future developments.
The article is well structured, the references seem to me to be adequate, but there should be a few more from other authors, and the conclusions presented seem to me to be logical. However, I think that extra care must be taken in the presentation of figures and tables so that the document is easier to read and understand, as well as the possibility of presenting a practical application at the end.
I made some comments to improve the quality of the article. I recommend that authors take into account the observations and resubmit the article.
- Specified comments
Comment 01: page 2, table 1
You should place the table so that it is not cut off when you change pages.
This situation appears several times throughout the text.
Please verify.
Comment 02: page 3, figure 1
The size of the text and dimensions of the figure must be a little larger to be able to read. Some values are impossible to read.
If you add a 3D image of the Y-type it would be more noticeable.
Comment 03: page 4, table 5
The table is confusing, it may be because it is part of one page and part of another.
Perhaps adding horizontal lines to separate the lines will be more understandable.
Comment 04: page 5, line 123
Where it is "stress(315MPa)" it should put spaces between the words, it should be "stress (315 MPa)".
This situation occurs several times throughout the text. Please check and correct.
Comment 05: page 5 in section "2.3 Strain gauge plan"
In section "2.3 Strain gauge plan" you indicate that you only measured the strains in monotonic loading.
What about repetitive or cyclic loading? Didn't you measure the extensions? Why? Perhaps it would be interesting to analyse the evolution of the field of extensions and possibly know the hysteretic behaviour.
You can, and should, address this issue by explaining your reasons.
Comment 06: page 9, line 354
Why don't you write "m2" instead of "sqm"? It gets simpler.
This situation is repeated several times throughout the text. Please check.
Comment 07: page 9, table 3
Table 3 is not referenced in the text.
Comment 08: page 7, table 5
You should avoid splitting the table. If you need to split it you should be careful to split it between rows.
Comment 09: page 8, figure 6
The text of graphics and legends is too small.
If you put the lines with colours it is easier to read.
The figure caption must be next to the figure and not on the next page.
Comment 10: page 9, figure 7
The graphics and text of graphics and legends are very small. Please review.
Comment 11: page 10, figure 8
Graphic and text of graphics and legends very small.
If you put the lines with colours, it is easier to read.
Comment 12: page 10, figure 9
I see no difference between Load types 1, 2 and 3, (a), (b) and (c), and between Load types 4 and 5, (d) and (e).
I think it would be better if you simplify the figure and put only two graphics, one for the Load type 1, 2 and 3 cases and the other for the Load type 4 and 5 cases.
I leave it to your discretion.
Comment 13: page 11, table 8
The table is split.
Comment 14: page 15, line table 15
The table is split.
Comment 15: page 17, lines 320 and 321
I think it might not be table 5.3. Please correct.
Comment 16: page 17, table 19
The table is divided, if there is a need to divide the table it must be in an area that does not cause disturbance to the reading. For example, before "Cycle".
Comment 17: page 19, figure 11
Figure with poor quality, the caption cannot be read.
Comment 18: page 20, figure 12
The text size could be a little bigger.
Comment 19: page 21, lines 394 to 396
I didn't understand the idea of dissipated energy, E, being adopted by attempts. You should better explain your idea.
Comment 20: page 22, line 413
When you refer in the text "various probability papers" you should indicate at least one reference.
The same situation appears elsewhere in the text. Please verify .
Comment 21: page 22, figure 14
Cannot read the figures. Try formatting them like figure 12 or 13 for example.
Comment 22: page 23, figure 15
Text on graphics cannot be read. Consider making it a little bigger.
Comment 23: page 24, before “6. Conclusion”
Since you are talking about design, I think that introducing one or two practical examples would improve the article.
It could be with one of the studied cases to later compare the experimental and design results.
Comment 24: page 25 and 26, about References
I understand that this article follows on in a series of articles concerning the study of a particular phenomenon, but, if possible, it should have more articles by other authors. It seems to me that of the 18 references presented, 9 are from the same author and that he is one of the authors of this article. Attention I'm not saying not to put your references.
Author Response
Reviewer #3
The authors appreciate your thoughtful comments and constructive suggestions, which are very helpful in improving the grammatical and technical quality of the paper. Your work is greatly appreciated. A complete revision of the manuscript has been performed according to your comments and suggestions. We hope that you are satisfied with them. If you have any questions or suggestions, please let us know and we will happy to make further improvements. The detailed responses to your comments are shown below:
Point 1
Page 2, table 1: You should place the table so that it is not cut off when you change pages. This situation appears several times throughout the text. Please verify.
Response
All of tables have been re-arranged not to be cut off when pages are changed. The same works have been done for the comments of No. 3, 7, 8, 13, 14 and 16.
Point 2
page 3, figure 1: The size of the text and dimensions of the figure must be a little larger to be able to read. Some values are impossible to read. If you add a 3D image of the Y-type it would be more noticeable.
Response
We have revised Figure 1. The specific descriptions and a 3D image have been added. Additionally, Figure 3 has been improved also.
Point 3
page 4, table 5: The table is confusing, it may be because it is part of one page and part of another. Perhaps adding horizontal lines to separate the lines will be more understandable.
Response
We have added some horizontal lines for better understanding for Fig. 3 as well as Fig. 5.
Point 4
page 5, line 123: Where it is "stress(315MPa)" it should put spaces between the words, it should be "stress (315 MPa)". This situation occurs several times throughout the text. Please check and correct.
Response
We have corrected those issues following your comments in the whole manuscript.
Point 5
page 5: in section "2.3 Strain gauge plan"
In section "2.3 Strain gauge plan" you indicate that you only measured the strains in monotonic loading. What about repetitive or cyclic loading? Didn't you measure the extensions? Why? Perhaps it would be interesting to analyse the evolution of the field of extensions and possibly know the hysteretic behaviour. You can, and should, address this issue by explaining your reasons.
Response
We tried to measure the strains under the repeated loadings, but the steel gauges broke down after some cycles of repeated loads with high intensities. Unfortunately, the results could not be included in this study. This part will be improved in the future studies.
Point 6
page 9, line 354: Why don't you write "m2" instead of "sqm"? It gets simpler. This situation is repeated several times throughout the text. Please check.
Response
We have checked the expression error.
Point 7
page 9, table 3: Table 3 is not referenced in the text.
Response
Table 3 has been referenced on Line 127 (page 6) in the revised manuscript.
Point 8
page 7, table 5: You should avoid splitting the table. If you need to split it you should be careful to split it between rows.
Response
The authors have confirmed those tables as mentioned in Point 1.
Point 9
page 8, figure 6: The text of graphics and legends is too small. If you put the lines with colours it is easier to read. The figure caption must be next to the figure and not on the next page.
Response
Fig. 6 has been improved with some color lines and the figure caption has been checked..
Point 10
page 9, figure 7: The graphics and text of graphics and legends are very small. Please review.
Response
The legend and graphics have been revised.
Point 11
page 10, figure 8: Graphic and text of graphics and legends very small. If you put the lines with colours, it is easier to read.
Response
The legend and graphics have been revised.
Point 12
page 10, figure 9: I see no difference between Load types 1, 2 and 3, (a), (b) and (c), and between Load types 4 and 5, (d) and (e). I think it would be better if you simplify the figure and put only two graphics, one for the Load type 1, 2 and 3 cases and the other for the Load type 4 and 5 cases. I leave it to your discretion.
Response
We have revised the figures. The last load stages have been modified and highlighted.
Point 13
page 11, table 8: The table is split.
Response
The split parts have been revised.
Point 14
page 15, line table 15: The table is split.
Response
The split parts have been revised.
Point 15
page 17, lines 320 and 321: I think it might not be table 5.3. Please correct.
Response
The number has been changed (New: Table A3) because the table has been arranged to be in APPENDIX A.
Point 16
page 17, table 19: The table is divided, if there is a need to divide the table it must be in an area that does not cause disturbance to the reading. For example, before "Cycle".
Response
This table (New: Table A3) has been arranged in APPENDIX A, and the split problem has been removed.
Point 17
page 19, figure 11: Figure with poor quality, the caption cannot be read.
Response
The figure has been improved with high quality caption. The figure number has been changed from Fig. 11 to Fig. 12.
Point 18
page 20, figure 12: The text size could be a little bigger.
Response
The legend and graphics have been revised. The figure number has been changed from Fig. 12 to Fig. 13.
Point 19
page 21, lines 394 to 396: I didn't understand the idea of dissipated energy, E, being adopted by attempts. You should better explain your idea.
Response
In Clause 4.2, a figure (additional Figure 11) is added to describe how to calculate the energy dissipation for better understanding.
Point 20
page 22, line 413: When you refer in the text "various probability papers" you should indicate at least one reference. The same situation appears elsewhere in the text. Please verify.
Response
1) We added the reference [21].
Ang, A. H-S.; Tang, W. H. Probability concepts in engineering Vol.1, Wiley, 2007.
2) Ang et al. [21] introduces some examples in Chapter 7, for constructing various probability papers with data base. Based on these examples, the probability models in this study were derived. This study suggested 3 types of probability papers, which were Normal, Log-normal, and Type-I. The results were plotted in Figure 14, and summarized in Table 21.
Point 21
page 22, figure 14: Cannot read the figures. Try formatting them like figure 12 or 13 for example.
Response
The figures have been revised, and the figure number has been changed from Fig. 14 to Fig. 15.
Point 22
page 23, figure 15: Text on graphics cannot be read. Consider making it a little bigger.
Response
The figures have been revised, and the figure number has been changed from Fig. 15 to Fig. 16.
Point 23
page 24, before “6. Conclusion”: Since you are talking about design, I think that introducing one or two practical examples would improve the article. It could be with one of the studied cases to later compare the experimental and design results.
Response
Because this study is in the beginning stage of development, it is quite difficult and may require long and tedious computational work to show the practical example cases in the current stage. In the future, we will try to show more practical examples. In the current article, the word of design in “design residual shear strength” is used to introduce the probability-based safety margin on the probabilistic residual strength after the action of repeated loads. In many limit state design codes, the design resistance is recommended with a proper safety margin based on the nominal resistance and the proper safety margin may be achieved with the resistance reduction factors.
Point 24
page 25 and 26, about References: I understand that this article follows on in a series of articles concerning the study of a particular phenomenon, but, if possible, it should have more articles by other authors. It seems to me that of the 18 references presented, 9 are from the same author and that he is one of the authors of this article. Attention I'm not saying not to put your references.
Response
Some more references have been added as follows:
- Suzuki, A.; Kimura, Y. Cyclic behavior of component model of composite beam subjected to fully reversed cyclic loading. Struct Eng. 2019, 145(4), 04019015.
- Suzuki, A.; Abe, K.; Suzuki, K.; Kimura, Y. Cyclic Behavior of Perfobond-Shear Connectors Subjected to Fully Reversed Cyclic Loading. Struct. Eng. 2021, 147(3), 04020355.
- Kisaku, T., & Fujiyama, C. Modeling the cyclic response of perfobond-rib shear connectors. Eng. 2017, 171, 1317-1324.
- Ang, A. H-S.; Tang, W. H. Probability concepts in engineering Vol.1, Wiley, 2007.
Author Response File: Author Response.docx
Reviewer 4 Report
In this study, residual shear resistance of Y-type perfobond rib shear connectors under repeated loading is investigated. Extensive experimental testing is conducted in several samples and results are presented. However, it is not clear how the results would be adding value to the current knowledge. Specifically, the authors have conducted similar tests and presented results in the past. It is not entirely clear how this current study is different from the past studies. Some specific comments are given below
- The directionality of the loads and its importance is mentioned in the Introduction, however, in the rest of the text, specifically in the conclusion it was not discussed. Further discussion in this regard would improve the manuscript.
- Some background study on residual shear strength models would be helpful. Is the proposed model applicable to any repeated loads or just one-directional repeated loads?
- Figure 1 needs more explanation.
- It is not explained clearly why the two samples behaved differently in Figure 13.
- How is the energy dissipation per cycle calculated?
- The number of tables may be reduced in the text and attached as an appendix. Instead, the primary takeaway from the tables should be discussed in-depth.
- Several grammatical errors were found in the Introduction.
Author Response
Reviewer #4
The authors appreciate your thoughtful comments and constructive suggestions, which are very helpful in improving the grammatical and technical quality of the paper. Your work is greatly appreciated. A complete revision of the manuscript has been performed according to your comments and suggestions. We hope that you are satisfied with them. If you have any questions or suggestions, please let us know and we will happy to make further improvements. The detailed responses to your comments are shown below:
Point 1
The directionality of the loads and its importance is mentioned in the Introduction, however, in the rest of the text, specifically in the conclusion it was not discussed. Further discussion in this regard would improve the manuscript.
Response
At the beginning of the conclusion, it is declared that “This study investigates the residual shear resistances after one-directional repeated loads on the Y-type perfobond rib shear connectors”. In abstract and introduction, the repeated loading types are explained additionally.
Point 2
Some background study on residual shear strength models would be helpful. Is the proposed model applicable to any repeated loads or just one-directional repeated loads?
Response
The model proposed in this study is applicable to just one directional repeated loadings. This limitation is described clearly at the beginning of the conclusion. Further studies need to be performed for different types of cyclic loads, such as fully reversed cyclic loadings in the future.
Point 3
Figure 1 needs more explanation.
Response
The authors have revised Figure 1. The specific descriptions and 3D image are added.
Point 4
It is not explained clearly why the two samples behaved differently in Figure 13.
Response
The description on the two results has been expressed on page 23, line 395 in revised version.
Point 5
How is the energy dissipation per cycle calculated?
Response
In clause 4.2, a figure (Figure 11) is added to describe how to calculate the energy dissipation for better understanding.
Point 6
The number of tables may be reduced in the text and attached as an appendix. Instead, the primary takeaway from the tables should be discussed in-depth.
Response
The long length tables of Table 17 to Table 20 have been arranged to Appendix A. The followings are the new table numbers.
|
Table 17 → Table A1 |
Table 18 → Table A2 |
|
Table 19 → Table A3 |
Table 20 → Table A4 |
Point 7
Several grammatical errors were found in the Introduction.
Response
The grammatical errors were checked and corrected with our best.
Author Response File: Author Response.docx
Round 2
Reviewer 4 Report
The authors have addressed the specific comments, but the main comment has not been addressed. The reviewer previously asked “how the results would be adding value to the current knowledge? Specifically, the authors have conducted similar tests and presented similar results in the past. It is not entirely clear how this current study is different from the past studies”. This comment has not been addressed by the authors. I understand, in this case, the load case is different (one-directional). But I am not convinced that the study presented in this manuscript is a different one from one of the past studies by the author and hence, adding value to the existing knowledge base.
Author Response
Round #2 – Reviewer #4
Point 1
The authors have addressed the specific comments, but the main comment has not been addressed. The reviewer previously asked “how the results would be adding value to the current knowledge? Specifically, the authors have conducted similar tests and presented similar results in the past. It is not entirely clear how this current study is different from the past studies”. This comment has not been addressed by the authors. I understand, in this case, the load case is different (one-directional). But I am not convinced that the study presented in this manuscript is a different one from one of the past studies by the author and hence, adding value to the existing knowledge base.
Response
The authors did not understand carefully the first comment and apologize for your inconvenience. Now, the authors believe we understand the meaning of your comments.
The perfobond rib models in the previous studies[8-11] are quite different from the models in this study: 1)rib height 50mm in 8-11 and 100mm in this study, 2)concrete strength 30MPa in 8-11 and 60MPa in this study, 3)applied loadings: fully reversed cyclic loads in 8-11, which is designed to be experienced in the shear connectors between steel beam and RC slab in multi-bay, multi-story frame structure during earthquakes, whereas one directional repeated loads in this study, which is designed to be experienced in the shear connectors at the anchor of tension cables.
The following is added in the introduction. However, the conclusion is not modified because it is quite difficult to compare the findings in this study with the results of previous studies.
The authors hope you accept our additional modification to improve the article and appreciate your valuable comments again.
“In the previous studies[8, 9, 10, 11] the stubby Y-type perfobond rib shear connectors are tested to be adopted for the steel beam-RC slab composite system in the multi-bay, multi-story frame. The stubby Y-type perfobond rib height is very short and 50mm high( the total height is 85mm including the root and dowel hole) to be embedded in the shallow depth RC slab(150mm deep slab specimens) and the concrete compressive strength is designed to be around 30MPa. In addition, the cyclic loads are applied to be fully reversed cyclic loadings to simulate the loading conditions during earthquakes. This study investigates the deteriorating shear strength capacities of Y-type perfobond rib shear connectors under the one-directional repeated loadings, in which the rib height is designed to be tall and 100mm high(the total height is 160mm including the root and dowel hole) to provide high shear resistances. Therefore, the embedded concrete slab in test specimen is 280mm deep and the concrete compressive strength is designed to be about 60MPa. The applied testing loads are designed to be one directional without any reversal loads, which may be experienced in the anchor systems of tension cables.”
Author Response File: Author Response.docx
