Damage Detection in External Tendons of Post-Tensioned Bridges

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Please find the revised version of the article enclosed.

Comments for author File: Comments.pdf

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

1.       The authors introduced too much related theories and the modeling process, these words are suggested to be condensed. However, the study should clearly explain what contribution has been made by former researches and, in particular, what limitation /weakness exists in each previous research. Authors should identify the gap of the knowledge from the review of the previous research to justify the significance of the current research topic.

2.       The conclusion should define the current study of key findings. The innovative contribution of this paper with respect to the state of the art should be emphasized.

3.       The words in Figures 4 and 6-9 are hard to be recognized.

4.       The Tendon Number in Table 2 is confusing. It’s hard to connect these number to the previous figures together.

5.       How does the damage in tendons affect the performance of bridges, e.g., the 10% cross-sectional area reduction.

6.       The field monitoring at a in-situ bridge is suggested to be added.

Comments on the Quality of English Language

1.       Some sentence is confusing for the reviewer. The English language should be revised for the whole manuscript by experts and professionals.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

This study investigates damage detection in the tendons of post-tensioned segmental box girder bridges, focusing on the vibration-based technique and its application in conjunction with the Precursor Transformation Matrix. However, I believe that revisions are necessary before publishing the paper. My recommendation is for Minor Revision. The specific review comments are as follows: 

 1.      Infrastructures is an international journal, and the reviewers suggest that the author should use the international unit (meters) instead of feet to annotate the structural dimensions and perform case calculations in the manuscript. The authors should carefully review and address similar issues by ensuring the use of international units.

 2.      How is vibration-based damage identification and localization manifested in the studied cases? The reviewers request the author to provide an explanation for this.

 3.      The author employs a combination of PTM and vibration analysis for tendon damage identification and localization in the manuscript. However, this study lacks comparisons with other advanced methods. The authors should supplement this content to further elucidate the advantages of the proposed method.

 4.      The authors should provide an overall flowchart to visually illustrate the proposed damage identification and localization method in the paper.

 5.      Chapter 5 in the manuscript still analyzes and discusses the results from Chapter 4. Therefore, the reviewers suggest merging the existing Chapter 4 and Chapter 5.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 4 Report

Comments and Suggestions for Authors

Manuscript which shown investigates damage detection in the tendons of post-tensioned segmental box girder bridges, focusing on the vibration-based technique and its application in conjunction with the Precursor Transformation Matrix. The topic has great practical application.

Even though the authors present it mainly from a theoretical perspective, I consider the manuscript to be very valuable.

Despite the high rating, I have critical comment and I believe that the method should be refined.

 

It is not always true to say that "when a tendon undergoes hypothetical damage equivalent to 10% cross-sectional loss, the axial internal force within that tendon decreases by approximately 10% and that the internal axial forces in the other tendons remain stable, with only slight increases up to maximum of 0.3%".

This statement is true for most typical bridge structures, but:

 

1. When a tendon undergoes hypothetical damage equivalent to 10% cross-sectional loss, the axial internal force within that tendon decreases by approximately 10% but that doesn't mean that when a tendon undergoes hypothetical damage equivalent to 30% cross-sectional loss, the axial internal force within that tendon decreases by approximately 30%.

 

2.  "The internal axial forces in the other tendons remain stable, with only slight increases up to maximum of 0.3%".

This distribution of internal forces is true with a large number of tendons. 

The smaller the number of these tendons, the more noticeable the interaction of the remaining ones.

 

3. The distribution of forces depends on the bending stiffness of the cross-section in the longitudinal and transverse directions (EJ_x and EJ_y). The higher the stiffness, the more evenly the stresses (forces in the tendons) are distributed.

 

In the summary, I maintain the high practical and theoretical value of the presented analyses, but I believe that before introducing that method for monitoring bridge structures, it should be confirmed experimentally and determine for which bridge parameters it can be safely used.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

In my judgement, the article is suitable for publication in the scientific journal Infrastructures in its current form.

Author Response

Thank you for your valuable comments that made our paper better.

Reviewer 2 Report

Comments and Suggestions for Authors

The manuscript has been revised according to the reviewers’ comments and suggestions, however, the following comments are still need to be modified.

1.       The previous comment was “The conclusion should define the current study of key findings. The innovative contribution of this paper with respect to the state of the art should be emphasized”. However, the modified conclusion needs to be condensed.

2.       The responses present “this method would not be effective in detecting damage to tendons unless each tendon is instrumented with a sensor”. Does the proposed method be practical?

Comments on the Quality of English Language

 English language is fine.

Author Response

Dear reviewer,

Thank you for your valuable comments. Please see our responses to your comments below.

Comment 1:

The conclusion has been modified per the reviewer's comment. Please see the attached track change Word file for the revised conclusion.

Comment 2:

To reflect the reviewer's valid viewpoint, the following sentence was added to the manuscript:

"Nevertheless, additional sensors and monitoring would impose additional costs and efforts, making this method less practical."