Experimental Study on the Performance of GFRP–GFRP Slip-Critical Connections with and without Stainless-Steel Cover Plates

Round 1

Reviewer 1 Report

I propose the expression "It is clear that a high-performance fastener can be obtained using ..." 21-24, replaced by a more correct one in meaning: "It is shown that a high-performance fastener can be obtained using ...".

It is necessary to justify the temperature range of environmental exposure, for which the results are reliable.

Author Response

The authors would like to thank the editor and reviewers for your detailed suggestions to improve the paper. The detailed point - by - point reply to the comments are submitted in the word file attached below.

Author Response File: Author Response.docx

Reviewer 2 Report

 

I have some comments which are presented below.

1. Line 42. The authors should use the proper name of ref. [2].
2. Line 48. The authors should use the proper name of ref. [3].
3. Line 57, line 287. The name “Hashomoto [5]” does not exist.
4. Line 65. It should be: Feo et al. [3].
5. Line 112. Table 1. Vickres hardness (MPa) – is the hardness unit correct?
6. Line 114. Figure 1. The drawing is missing some dimensions. What is the placement of bolts? The authors must complete this information. On what basis was such a spacing of bolt holes (along the length and thickness of joined elements) adopted?
7. Line 120. The authors mentioned: “It was determined that the grit-blasting causes an increase in the Vickers micro-hardness 120 values of all of the materials,...”. In table 1 the authors presented the Vickers hardness. Therefore, the authors have to specify what kind of hardness is analyzed, which obviously depends on the amount of load at which the hardness is measured by the Vickers method.
8. Line 126. Why did the authors choose such grit-abrasive? What were they guided by?
9. Figure 2. The authors must complete the information that the device was used to make the pictures shown in Fig. 2.
10. Figure 2. The figures are of poor quality and in most cases no differences can be seen on the surface of the treated materials. A better solution would be to present the roughness profile or topography of the 3D surface. In my opinion, this drawing does not reflect the essence of differences in surface treatment, and in this arrangement it is unnecessary. It is necessary to replace these other results.
11. 3 and Fig 1. Presented the different scheme of specimens. Why?
12. Line 187. Was the hardness or microhardness tested? There is no information on the method of measuring hardness or microhardness. The authors must complete it. What was the number of samples analyzed? How many measurements were made? There is no information about the device.
13. Line 192. There is no information on the method of measuring surface roughness. What was the number of samples analyzed? How many measurements were made? There is no information about the device. What surface roughness parameters were analyzed? The authors must complete it.
14. Line 244. Table 7. The results in the table are a bit incomprehensible. Please explain what the average values ​​are for? Is this the average of the specimens: G-G-1 and G-G-2? Only with two measurements? Is the value for example for slip load for G-G1 specimen average with some measurements? What was the number of measurements in the series? What statistic was used to calculate the average of only two measurements? What was the average mean error then? According to what statistics was it determined? What was the standard deviation?
15. These above notes also apply to other tables.
16. Line 246. Fig. 5 (and Figs. 6-8). There are no deviations from the average value for individual results. There is no information as to whether these are average measurements.

 

General comments:

17. The authors mention measurements of surface hardness and roughness, and there are no results of these quantities. It is necessary to supplement. If it is not there, unfortunately, but the reference to surface roughness or hardness is completely pointless.
18. The authors should use “joint/s” instead of “connection/s”.
19. The failure analysis should be done. This part of article must be completed.
20. The literature is prepared carelessly. There are many mistakes. The authors' citation style should be the same. The authors use the name and surname once and the surname once. Moreover the style of presentation the reference in the references list is different (e.g. please compare: [2], [8], [14], [21] and [20]). It is necessary to standardize literature citation.

 

 

       I have suggested the work to be re-written and reviewed.

 

Author Response

The authors would like to thank the editor and reviewers for your detailed suggestions to improve the paper. The detailed point - by - point reply to the comments are submitted in the word file attached below.

Author Response File: Author Response.docx

Reviewer 3 Report

Dear Authors, thank you for the interesting paper. I have some comments:

- in the text of the article, you refer to the literature of Hashimoto et al. [5], but the literature [5] is Kunitaro and Kunitomo - please correct it,

- you have also tested the connection with prestressed bolts (chapter 3.4), as you state, in this case the load-bearing capacity of the joint is greatly affected by the pre-tension of the high-strength bolts, which is lost over time due to creep in GFRP. In how long will the preload completely disappear? Isn't there little 30 days for such a test? Haven't you considered a long period of time?

Author Response

The authors would like to thank the editor and reviewers for your detailed suggestions to improve the paper. The detailed point - by - point reply to the comments are submitted in the word file attached below.

Author Response File: Author Response.docx

Round 2

Reviewer 2 Report

The most of the comments have been included in the revised version of the article.

I accept the revised article in the present form.