Numerical Simulation and Experimental Study on Detecting Effective Prestress of 1860-Grade Strands Based on the Drilling Method
Round 1
Reviewer 1 Report
1. Could you explain what is the effective tension F_N with mention of force?
2. What role does the force (F_T) in the tangential direction play here? Could you write more about the influence in the tangential direction? If this plays an important role, then how can its influence in the tangential direction during drilling be calculated?
3. Check the units of measurement: Gpa change to GPa, Mpa to MPa.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
The study aimed to investigate prestressing strand behavior. They established coefficients A and B, representing stress-strain relationships using micro-hole release theory. Finite element simulations in Midas FEA NX software were employed to model stress release during strand drilling. Practical experiments on a custom tensioning platform validated their findings. The results indicated a linear correlation between axial tension and strain. Stress release was positively linked to tension stress and hole edge distance, with decreasing effects at greater hole margins. A recommended test program involved a 3-6mm hole margin, 1.5mm or 1.8mm drilling diameter, and 2.5mm drilling depth. Coefficients A and B were determined as 1.12 and 57.84, respectively. However, it is crucial to make minor changes and respond to inquiries before contemplating publication.
1. What were the specific values for coefficients A and B that the authors determined in their study?
2. Can you provide the exact range of hole edge distances (in millimeters) that the authors found to have a positive correlation with stress release?
3. In the recommended test program, what was the suggested range for the hole margin (in millimeters)?
4. What were the drilling diameters (in millimeters) considered in the study, and which one was found to be more reasonable based on their findings?
5. When analyzing the strain release effect, what value (in millimeters) of drilling depth was found to result in a more noticeable strain release?
6. What was the observed linear correlation value between measured strain values and tensile strength for a 1.5mm drill diameter and a 2.5mm drilling depth?
7. Could you specify the exact values (in numerical terms) of axial tension and axial strain that were found to have a linear relationship in the study?
8. What is the rationale behind opting for the Midas FEA NX software, even though you referenced previous research in your introduction that utilized Abaqus?
Author Response File: Author Response.pdf
Reviewer 3 Report
The reviewer thanks the authors for their contribution. In general, the numerical and experimental work is appreciated because the findings are useful information for bridge assessment applications. Nonetheless, the goal of the work must be better explained within Abstract, Introduction and Conclusions. Furthermore, the publication in the “Coatings, MDPI” is not recommended unless the following suggestions are taken into account:
A) Please polish the abstract. Please add sentences to explain the meaning, the main points, the improvement and the promising application of the study. The logic should also be improved.
B) Introduction. The current state of knowledge relating to the topics of the article has not been covered and clearly presented, and the authors’ contributions and findings are not emphasized. In this regard, the authors should make their effort to address these issues.
C) Introduction. In the literature, some static nondestructive methods were developed to identify the prestress losses in existing concrete bridges. Please refer to this issue through the following references:
- https://doi.org/10.1142/S0219455418501249
- https://doi.org/10.3390/ma15103583
D) Figures 1-3 should be illustrated in one figure, i.e., in Figure 1(a), (b) and (c). Please modify it.
E) Figure 5. The values of the stresses should be reported without any decimal, while the percentage errors should be reported with one decimal only.
F) The geometric and mechanical characteristics of the experimental layout, which has been used, have not clearly been illustrated. Please provide more information and introduce figures with schemes of the strands which have been tested.
G) Please cite the software “Midas FEA NX” in the references.
H) Please insert tables which list the types of finite element used, with the corresponding amounts within the finite element models and mesh sizes of the strands.
I) The further work should be mentioned at the end of the article. Please mention.
J) Additional comments should be added in regard to the practical value of this work, and how the industry can profit from this article.
The English requires a moderate editing.
Author Response File: Author Response.pdf
Round 2
Reviewer 3 Report
The required revisions were carried out and the manuscript can be accepted for publication.
English language requires a minor editing.
