Operational Modal Analysis on Bridges: A Comprehensive Review
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsDear authors
This paper focused on the field of the health monitoring of bridge by operational modal analysis. I summarized so many literiture on this topic, and the paper was well orgnized and presented. However, some issues on wirting and figures should also be improved.
1) The writing of the abstract must be improved, since so many word used to introduce the background rather than the main findings of the paper;
2) In introduction section, it is recommended to introduce the other NDTs in evaluating damage of bridge, and compare with the operational modal analysis;
3) It is recommended that list all abreviations ahead of the Introduction section.
4) Figure 1, it it recommended adjusting the flow to horizontal line.
5) Figure 2, pay attention to the copy right, since it is referred.
6) Figrue 3, turn it to horizontal direction for ease reading.
7) section 2. Instrumentation, it is recommended that additional informations of devices should be added. it is too short compared with other sections.
8) It is recommended that the authors should reduce the references to make it more concise for readers to find the most relevant references.
Author Response
Please see the attachment.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for AuthorsAttached file
Comments for author File: Comments.pdf
No
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Reviewer 3 Report
Comments and Suggestions for AuthorsThe reviewer thanks the authors for their contribution. The “review” is appreciated because some findings are useful information for bridge assessment applications. Nonetheless, the publication in the “Infrastructures, MDPI” is not recommended unless the following suggestions are taken into account:
1) The article could be improved following three specific directions to provide a clearer message to the reader that could be confused by the extension of writing and the number of references. (1) Introduce a table for each section where the existing literature is discussed to briefly and schematically characterize each reference (e.g. authors, year, lab or numerical experiments, topic, findings). This could help to furnish more strength and significance to the state-of-the-art. (2) Introduce original figures with schemes to explain the driving ideas traced by the literature review. This also could help the reader to have a more straightforward idea of the material. (3) The original contribution of the article is not clear. Introduction and concluding remarks should be improved to sharply emphasize the contribution of existing methods and clearly trace further developments.
2) Please insert a graph “Number of contributions vs. Year” related to the works on the operational modal analysis on bridges.
3) It is also necessary to design a flowchart to introduce the process of the article.
4) Please enlarge the figures 1, 2 and 3. The dimension of the texts within the figures is small.
5) Section 5.1. The changes in natural frequencies have been studied to predict the prestressing losses in concrete post–tensioned girder-bridges and steel post–tensioned ones. Specifically, the use of the fundamental frequency is not recommended for concrete girder-bridges subjected to slight cracking and for steel girder-bridges due to the presence of the tendon deviators along their spans. Vice versa, the fundamental frequency is recommended to estimate their flexural stiffness. Please refer to these issues through the following references:
- https://doi.org/10.1016/j.engstruct.2016.09.017
- https://doi.org/10.1016/j.jcsr.2023.107854
Comments on the Quality of English LanguageEnglish language requires a moderate editing.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Reviewer 4 Report
Comments and Suggestions for AuthorsPlease see the attached file.
Comments for author File: Comments.pdf
Overall fine but needs a grammar and spelling check.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Reviewer 5 Report
Comments and Suggestions for AuthorsThis review article focuses on the operational modal analysis of the dynamic characteristics of bridges, including damage detection. The manuscript is well written and easy to follow, and it summarizes hierarchical approaches to evaluate the structural dynamic behavior and potential damages under varying loads and conditions. There are some points to improve.
(1) Page 5: As to data gathering, the technique of drone detection should be mentioned, which not only provides a 3D model of a bridge or a member, but also serves as an alternative to other methods. The authors are suggested to review this.
(2) Page 6: In the section of dynamic Analysis, the reviewer suggest the authors to add tables to quantify different methods, in terms of e.g. precision, implementation time, number of processed data points, frequency characteristics, etc. Such a quantitative comparison would bring more information for potential readers in both research and engineering communities. This comment can also solve the problem of the sentence (NOT PROVED) “There is generally a very minor difference in the results of various modal identification techniques in the time or frequency domain. However, for optimal reliability and efficiency, the SSI method stands out as…” on Page 20.
(3) Page 12: As to damage detection using modal parameters, the reviewer suggest the authors to illustrate different damage types (local and/or global) by pictures and relate them to methods used, so as make the manuscript more comprehensive.
(4) Page 16: As to machine learning (ML), the workflow of the mentioned ML techniques should be provided regarding preparation of datasets, identification of input and output parameters, random split, and performance indicators, refer to e.g. 10.1016/j.jrmge.2022.10.014. The authors are also suggested add a table of performance metrics for different ML models considering RMSE, R, etc., so readers can know how to choose ML techniques according to their aims.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Round 2
Reviewer 3 Report
Comments and Suggestions for AuthorsThe required revisions were carried out and the manuscript can be accepted for publication as a "Review".
Comments on the Quality of English LanguageEnglish language requires a moderate editing.
Reviewer 4 Report
Comments and Suggestions for AuthorsThank you for addressing the required revisions. The paper can be accepted in its current form for publication.
