Methodology for Assessing the Technical Condition and Durability of Bridge Structures

Round 1

Reviewer 1 Report

The paper presents an algorithm for assessing and predicting the technical condition of bridge elements.

The proposed methodology aims to determine an advanced engineering tool for assessing their reliability and durability.

The theoretical foundation of the methodology is a reliability model and residual lifetime prediction of bridge elements, based on Markov’s theory.

The algorithm for assessing and predicting the technical condition consists of seven main steps.

The introduction provides a sufficient background, but in my opinion, it is necessary to improve it.

The authors well describe numerous deterministic/probabilistic tools and methods that concern the reliability of constructions. However, they did not recall the factor method introduced by ISO 15676. I believe it is a method that well completes the background on the topic.

The research design is appropriate, and methods are adequately described.

However, it could be useful to clarify whether the study has only a theoretical character or there are experimental applications to case studies.       

The results are clearly presented and conclusions are supported by the results.

Author Response

Thank you for your comments. We have improved the introductory section and added the recommended ISO 15676. The text is as follows:

ISO 15686 [18] describes a factorial method designed as a tool to enhance the assessment of the service life of structures. The method utilizes modified coefficients for each factor group from A to G (quality of components; design level; work execution level; indoor environment; outdoor environment; in-use conditions; maintenance level). It is considered that any of these variables or their combination can impact the service life of the entire structure. However, there are studies indicating that the realistic range of coefficients is significant. Therefore, users of the ISO 15686 methodology may struggle to select appropriate values for the coefficients without in-depth knowledge of materials and local construction practices [19], posing limitations on the application of the factorial method.

The practical implementation of the proposed method is scheduled for future research.

Reviewer 2 Report

This paper presents an interesting work on a Markov Theory based approach to predict the remaining lifetime of operational bridges. The paper is well-written and organized, validated through a numerical/theoretical model. Some comments are required to be addressed before acceptance.

In Section 4, how did those values of λ be chosen in practice? Please clarify this point.

Again in Section 4, regarding the numerical experiment on remaining lifetime prediction, what’s the key parameter here? Is the aforementioned value of λ?

In the Conclusion Section, saying “a certain period (approximately 10-20 years)”, it’s suggested to keep consistent as the previous discussions, i.e., 10-15 years.

In Section 3, more references related to the failure rate function/Reliability evaluation/life prediction need to be provided, e.g., DOI: 10.1016/j.engfailanal.2010.09.030, DOI: 10.1080/13467581.2021.2024201

Again, the core sections are mainly relying on references, [13], [17], [18], some recent works related to the topic of bridge condition assessment/monitoring, and reaming life predictions, and especially for works relevant to Markov Theory based approaches, are suggested to strength the introduction, e.g., DOI: 10.1109/TR.2015.2439132, DOI: 10.1016/j.dibe.2023.100162, DOI: 10.1109/TR.2010.2054173

Only two different values of λ are investigated and compared in Section 4, and it’s suggested that results with different values of λ are provided in Section 4.

The accessible links for references [13], [18] are suggested to provide, as could be interesting and helpful to readers.

Author Response

Thank you for your comments. With some comments taken into account, we have agreed and made corrections to the text. For certain questions, we provide detailed answers. Also we have improved the introductory section.

1. In Section 4, how were the values of λ practically chosen? Please elaborate on this point.

To close question 1, we consider it appropriate to add the following text to line 415 in the document:

Taking into account the condition that the design service life of the bridge is set at 100 years, from equation (17), the failure rate ? can be obtained. Therefore, if ? = 0.0128, the structure will achieve the reliability Pcr after 100 years of operation. The actual service life of individual critical elements of the bridge may be around 60-65 years. For such structures, the failure rate ? will be 0.02. Therefore, for calculations, the values ? = 0.02 and ? = 0.0128 were chosen.

2. Furthermore, in Section 4, regarding the numerical experiment on predicting residual life, which parameter is crucial here? Is it the aforementioned value of λ?
The failure intensity λ is a key parameter that needs determination. Once λ is known, the reliability of the structure at any given time can be determined using equation (27). On the other hand, from relation (27), with the known reliability at the time of inspecting the structure \(t=t_e\), the corresponding value of intensity λ is determined. Since equation (27) is transcendental, one of the approximate methods (such as the method of successive approximations) or a graphical method (Figure 6) can be applied for this purpose.

3. In Section 4, only two different values of λ are investigated and compared, and it is anticipated that the results with different values of λ will be presented in Section 4.
Figures 5a and 5b depict plots of the probability function (a) and degradation rate (b) for selected failure intensities \(? = 0.02\) and \(? = 0.0128\). The authors opted to limit the presented examples to these values because for any other values of failure intensities ?, the graph shape is similar.

4. The mentioned works [13] and [18] may not have a DOI identifier, but they could be available on the internet. For example, access to [13] might require registration on the website through a personal account.

Reviewer 3 Report

The manuscript proposed a method to determine and forecast the technical condition of bridge elements, which could serve as an advanced engineering tool for assessing reliability and durability. However, there are several flaws that make the paper cannot be accepted as it stands. The authors are invited to address the following outstanding comments and revise their manuscript accordingly.

1) Lines 360-392. The comments on equations are insufficient. The authors need check all parameters and supplement them.

2) The authors need to supplement some of the information in Figure 5, such as units, etc.

3) The format of the references is confused, and the authors need to make unified revisions according to the requirements of the journal.

4) The language in the manuscript could benefit from improvement. The authors are encouraged to seek assistance from professional language services or AI-aided language polishing tools, such as ChatGPT, to enhance the clarity and readability of their writing.

5) The author needs to supplement the latest developments in the review section.

6) It is suggested that the proposed method should be used in a practical project. Or it can be used directly in experiments to improve persuasiveness. Maybe in future studies.

7) The following literature maybe useful for improving your quality:

① Numerical simulations of the failure process of anaclinal slope physical model and control mechanism of negative Poisson’s ratio cable. Bulletin of Engineering Geology and the Environment, 2021, 80: 3365-3380.

② Investigating the effect of water quenching cycles on mechanical behaviors for granites after conventional triaxial compression, Geomechanics and Geophysics for Geo-Energy and Geo-Resources, 2022, 8: 77.

The manuscript proposed a method to determine and forecast the technical condition of bridge elements, which could serve as an advanced engineering tool for assessing reliability and durability. However, there are several flaws that make the paper cannot be accepted as it stands. The authors are invited to address the following outstanding comments and revise their manuscript accordingly.

1) Lines 360-392. The comments on equations are insufficient. The authors need check all parameters and supplement them.

2) The authors need to supplement some of the information in Figure 5, such as units, etc.

3) The format of the references is confused, and the authors need to make unified revisions according to the requirements of the journal.

4) The language in the manuscript could benefit from improvement. The authors are encouraged to seek assistance from professional language services or AI-aided language polishing tools, such as ChatGPT, to enhance the clarity and readability of their writing.

5) The author needs to supplement the latest developments in the review section.

6) It is suggested that the proposed method should be used in a practical project. Or it can be used directly in experiments to improve persuasiveness. Maybe in future studies.

7) The following literature maybe useful for improving your quality:

① Numerical simulations of the failure process of anaclinal slope physical model and control mechanism of negative Poisson’s ratio cable. Bulletin of Engineering Geology and the Environment, 2021, 80: 3365-3380.

② Investigating the effect of water quenching cycles on mechanical behaviors for granites after conventional triaxial compression, Geomechanics and Geophysics for Geo-Energy and Geo-Resources, 2022, 8: 77.

Author Response

Thank you for your comments and your assessment.

All parameters have been checked in lines 360-392.
Units of measurement were added for the time scale on Figures 5, while others remain dimensionless.
References have been formatted according to journal requirements.
English grammar has been reviewed.
The Introduction section has been expanded, and additional sources have been added.
The practical implementation of the proposed method is planned for future research. 

Reviewer 4 Report

This is an interesting and very relevant work. It is very well structured and documented. The work methodology is well thought out, backed up by the results obtained.

I have only one minor comment: the text should be carefully checked, as many words appear together throughout the manuscript.

As an example:

- Line 13: It says "isproposed" and should read "is proposed".

- Line 14: It says "experimentof" and "methodologywas" and should read "experiment of" and "methodology was", respectively.

- Line 16: It says "lifetimeof" and "elements.First" and should read "lifetime of" and "elements. First", respectively.

- Line 17: It says "isproposed" and should read "is proposed".

- Line 38: It says "orstochastic" and should read "or stochastic".

Author Response

Thank you for your comments and your assessment.

We have agreed and we have reviewed and made corrections to the text.

Also, we have improved the introductory section.

Reviewer 5 Report

The paper addresses a methodology for assessing the technical condition and durability of bridge structures.

The research is interesting, and the novelty of the approach is mentioned. However, it lacks a background, namely a review of what is done in other countries. This would contribute to an improved significance of the work.

The Abstract is a bit lengthy, and some spacing is missing between words.

 In the "Introduction" section, the motivation should be highlighted at the end, as well as presenting the contribution and how the manuscript is structured.

In "Materials and Methods", an image should be presented to better support the seven groups of structural elements.

The structure of the paper lacks sub-sections. This is especially relevant in "Results" and "Discussion".

More references should be presented, again to support the background and motivation for doing the study.

Minor revisions required

Author Response

Thank you for your comments and your assessment.

We have reviewed and made corrections to the text.
In the Abstract section, spaces have been added.
The Introduction section has been expanded, and additional sources have been included to strengthen the motivation.
In the Discussion section, subsections have been added. 

Round 2

Reviewer 2 Report

All comments have been addressed by the authors. The manuscript can be accepted in its current form.

Author Response

We are grateful for your valuable advice and assistance in improving our work.

Reviewer 3 Report

This manuscript can be accepted for publication.

Author Response

We are grateful for your valuable advice and assistance in improving our work.

Reviewer 5 Report

Thank you for introducing changes to the manuscript.

In my perspective, the quality and readability of the paper increased substantially. Nevertheless, I find some shortcomings, namely the absence of a figure evidencing the elements under discussion and what is being done in other countries. Of course, I will not make a case out of it because this is part of the body of knowledge for most experts interested in this research. Yet, I must strengthen this aspect because it would improve, in my opinion, the quality and scientific soundness of the work.

N/A

Author Response

Thank you for your recommendations; we have taken them into account and added the Conceptual Model and Research Motivation illustration to enhance motivation and scientific justification. We are grateful for your valuable advice and assistance in improving our work.

Author Response File: Author Response.docx