Risk Assessment of Terrestrial Transportation Infrastructures Exposed to Extreme Events

Round 1

Reviewer 1 Report

I have a few comments that might be usefully addressed to improve the overall quality of the paper and some minor observation:
-    Line 35 – Dire, should be Direct;
-    Line 103 – UNDRR should be explained at first use;
-    The introduction should be more detailed with some other papers result in this field. Some of the papers are already cited, but the introduction should contain a little bit more presentation of other reaserchers works. 
-    The main content of the paper is very well written, but the conclusions need improvement, now they are vaguely written text in order to highlight the results obtained.
-    The experimental program is detailed and the quality of the results’ discussion in its current form satisfies the requirements necessary for a research paper.
The paper is therefore very well suited to this journal. The authors are to be commended on the professional quality of the research and the paper.

Author Response

Thanks a lot for your valuable comments. A point-by-point response to the comments is given below.

1) Line 35 – Dire, should be Direct;

Actually, the term "Dire" was used to denote severe consequences. It has been changed to "Consequences" to avoid misunderstandings

2) Line 103 – UNDRR should be explained at first use;

Agree. However, the terminology part of the paper has now been removed to shorten the paper.

3) The introduction should be more detailed with some other papers result in this field. Some of the papers are already cited, but the introduction should contain a little bit more presentation of other researchers works. 

The section "Risk assessment of terrestrial transportation infrastructures in literature", which presents other researchers works as well as identified gaps within the topic was moved to the introduction section. In addition, the introduction on line 26-46 has been supported by references.

4) The main content of the paper is very well written, but the conclusions need improvement, now they are vaguely written text in order to highlight the results obtained.

The conclusions have been extended with e.g. with description on how the obtained results can be directly used by the infrastructure owner

5) The paper is therefore very well suited to this journal. The authors are to be commended on the professional quality of the research and the paper.

Thank you very much!

Reviewer 2 Report

Risk assessment of terrestrial transportation infrastructures exposed to extreme events

 

The manuscript introduces a general framework for the assessment of multiple risks for infrastructures affected by extreme events. The methodology can be applied to several types of risks, both natural and human-related ones.

1) The paper proposes several applications; unfortunately, it is not clear if the authors developed such applications, or if they review applications of others. Indeed, it seems that the present paper is a review paper, not an article.

 

2) The text is very clear; the authors made use of appropriate English. Unfortunately, it is not always concise. Also, the authors deeply fragment the text in an excessive number of sections, subsections, and sub-subsections.

 

Also, I have the following major concerns:

1) By reading the manuscript, I have the impression of reading a project proposal, a technical report, or a book chapter. Unfortunately, not a scientific paper. The authors should carefully consider this last aspect, rearranging the manuscript accordingly.

• For instance, subsection 2.1 just introduces a very well-known range of terms.

 

• Most of section 2 should be found in a book chapter, but not in a scientific paper.

 

• Also, several activities (already carried out by others) are reported, resulting in a low degree of novelty.

 

• Conversely, there are very important paragraphs (subsection 2.3) that, coherently with the title and aim of the paper, should be deeply discussed. Indeed, subsection 2.3 is the only one that could provide novelty in the manuscript introduction.

 

• Line 1: This manuscript should not be considered as an “Article”. Perhaps it could be associated with a “Review” paper.

 

• The paper is too long and heavy to read. Considering that there are no significant aspects of novelty (at least in the first 15 pages), I believe that the authors can shorten the length of the text, proposing a simpler and more concise manuscript. Sometimes, I have the impression that the authors describe very simple concepts in detail to make them more complex.

 

2) Some really important extreme events are not introduced; coherently with the comprehensiveness of the paper, the authors have to discuss the impact of these events.

• The authors have to consider subsidence events and, in general, surface motion impacting road surface regularity and roughness (i.e., subsidence, sinkholes, uplift, and swelling). These natural extreme effects seriously affect infrastructures’ serviceability. Such events are very well known and the impact of those events with infrastructure monitoring and management is largely investigated by the academic community.

 

• The same applies to rockfalls impacting vehicles on roads.

 

Moreover, a minor remark:

• Lines 26-41: A very clear and concise paragraph. It should be supported by some relevant references. There are tens of appropriate relevant and recent papers on this subject.

Author Response

Thank you for your valuable comments! A point-by-point response is given below:

1) The paper proposes several applications; unfortunately, it is not clear if the authors developed such applications, or if they review applications of others. Indeed, it seems that the present paper is a review paper, not an article.

The content of the steps within the framework (Section 2, previously section 3) is developed and conceptualized by the authors. However, the framework also refers to the literature, especially within the subsection 2.4.1 and 2.4.2 on assessment of direct and indirect consequences. Even if the paper contains little new developments within these topics, they were nevertheless included to provide a more complete overview of the risk assessment. The application examples (Section 3, previously section 4) are also developed by the authors within the SAFEWAY project.

2) The text is very clear; the authors made use of appropriate English. Unfortunately, it is not always concise. Also, the authors deeply fragment the text in an excessive number of sections, subsections, and sub-subsections.

The text was with reviewed with respect to consistency and structuring. The number of sub-sub sections was reduced.

3) By reading the manuscript, I have the impression of reading a project proposal, a technical report, or a book chapter. Unfortunately, not a scientific paper. The authors should carefully consider this last aspect, rearranging the manuscript accordingly. (i) For instance, subsection 2.1 just introduces a very well-known range of terms. (ii) Most of section 2 should be found in a book chapter, but not in a scientific paper. (iii) Also, several activities (already carried out by others) are reported, resulting in a low degree of novelty. (iv). Conversely, there are very important paragraphs (subsection 2.3) that, coherently with the title and aim of the paper, should be deeply discussed. Indeed, subsection 2.3 is the only one that could provide novelty in the manuscript introduction.

To rearrange the paper in accordance with these comments, Section 2 was removed. The most relevant content of section 2 was moved to other sections, e.g. section 2.3 was moved to the introduction part.

4) Line 1: This manuscript should not be considered as an “Article”. Perhaps it could be associated with a “Review” paper. The paper is too long and heavy to read. Considering that there are no significant aspects of novelty (at least in the first 15 pages), I believe that the authors can shorten the length of the text, proposing a simpler and more concise manuscript. Sometimes, I have the impression that the authors describe very simple concepts in detail to make them more complex.

Even if parts of the risk assessment framework contains literature review to provide an overview of all risk assessment steps (as mentioned in point 1), the main parts are novel contributions. The development and conceptualization of the steps within the framework (Section 2, previously section 3) is a novel contribution to bridge the gap between general risk assessment frameworks and specific risk assessments of terrestrial transportation infrastructures in literature (that focuses on specific risk component, on specific hazard types and/or specific assets). The application examples, e.g. the development of a fragility curve of bridge scour are also novel contributions. Section 2 was removed for a more concise manuscript.

5) Some really important extreme events are not introduced; coherently with the comprehensiveness of the paper, the authors have to discuss the impact of these events. The authors have to consider subsidence events and, in general, surface motion impacting road surface regularity and roughness (i.e., subsidence, sinkholes, uplift, and swelling). These natural extreme effects seriously affect infrastructures’ serviceability. Such events are very well known and the impact of those events with infrastructure monitoring and management is largely investigated by the academic community.

Surface motions from e.g. subsidence, sinkholes, uplift, and swelling were added in Table 1.

6) The same applies to rockfalls impacting vehicles on roads.

Landslides were changed to "Gravitational mass movements (Landslides, rock-falls etc.)"

7) Moreover, a minor remark: Lines 26-41: A very clear and concise paragraph. It should be supported by some relevant references. There are tens of appropriate relevant and recent papers on this subject.

The text is supported with relevant references.

Reviewer 3 Report

The paper deals with the complex and challenging task of evaluating in a holistic fashion the risk of terrestrial infrastructure. The paper worth the publication provided that the comments reported in the pdf file attached are addressed:

1. the introduction lacks in literature. I provide some suggestions in the attachement
2. section 2.2. Ok the difference between quantitative and semi-quantitative methods for risk assessment. However, an effective way to assess risk is to quantify the expected losses. Moreover, authors do not talk about convolution of hazard, vulnerability and exposure which are the basic risk components. Little bit more discussion is needed here even if you do it later in the paper
3. line 190: holistic methods for risk evaluation of bridges (for example) already exist. See the suggested references
4. the same at line 210
5. in table 1: collisions of ships and vehicles are already recognized by many structural codes as design actions for bridges. Therefore bridges should already have a sufficiently low risk against these events 
6. Section 3.5: one important step in this regard is the infrastructure inventory. How do the authors propose to perform this step?
7. figure 3: this figure could be improved. blue backgrounds are different for example. Some characters are out of the frames.
8. table 6: does the exposure consider the number of daily users of certain infrastructure or the transit of dangerous goods?

Comments for author File: Comments.pdf

Author Response

Thanks a lot for your valuable comments and good suggestions for additional literature. 

1) the introduction lacks in literature. I provide some suggestions in the attachement

The suggested references have been included.  In addition, several references from the reference list have been referred to in the introduction. The section "Risk assessment of terrestrial transportation infrastructures in literature", was moved to the introduction section.

2) section 2.2. Ok the difference between quantitative and semi-quantitative methods for risk assessment. However, an effective way to assess risk is to quantify the expected losses. Moreover, authors do not talk about convolution of hazard, vulnerability and exposure which are the basic risk components. Little bit more discussion is needed here even if you do it later in the paper

Based comments from other reviewers, Section 2 was removed. The most relevant content of section 2 was moved to other sections, e.g. section 2.3 was moved to the introduction part.

3) line 190: holistic methods for risk evaluation of bridges (for example) already exist. See the suggested references

Text is modified, to include this reference. "There is a lack of studies that describe the identification of risk scenarios as part of the risk assessment framework, in a similar way that (M. Pregnolato 2019) describes holistic methods for risk evaluation of bridges."

4) the same at line 210

The suggested reference was included into the following line:  Some work has been done for other type of natural hazards such as flooding and flood-induced scour [] [].

Also, the following text has been added: "For instance, the Italian guidelines on risk classification and management of existing bridges group bridges into risk classes for prioritization of detailed assessment and funds allocation. Nevertheless, the application of the framework to real road networks has been found to provide conservative results and do not enable the ranking of bridges belonging to the same class given their qualitative nature (Santarsiero, Masi og Picciano 2021)."

5) in table 1: collisions of ships and vehicles are already recognized by many structural codes as design actions for bridges. Therefore bridges should already have a sufficiently low risk against these events 

That is true. Design codes themselves are the initial sources of risk reduction and risk mitigation. Nevertheless, the actual risk of systems change with time for different reasons thus it is important to measure it during the lifetime of the asset.

6) Section 3.5: one important step in this regard is the infrastructure inventory. How do the authors propose to perform this step?

The following lines are included at the end of section 3.5 to recognize the difficulty in gathering all data from assets and exposure required for a risk assessment:

It is worth noting that the implementation of the proposed framework is based upon the assumption that an inventory of the infrastructure assets is provided by the infrastructure owner. However, the unavailability of high-quality inventory data is an issue shared by many countries. One of the main drivers of this problem is the lack of a systematic data collection procedure. Thus, some efforts have been made to propose protocolled taxonomy and methods for data collection, aiming at unifying databases into a functional structure ready to be used in risk assessment frameworks (e.g.,Pregnolato 2019, Santarsiero et al 2021).

7) figure 3: this figure could be improved. blue backgrounds are different for example. Some characters are out of the frames.

The Figure has been improved according to these comments

8) table 6: does the exposure consider the number of daily users of certain infrastructure or the transit of dangerous goods?

No, but this is suggested to be included as part of the consequence assessment. The safety of the users is not considered directly, i.e., cases where road or railway users are directly injured by an extreme event are not considered and the focus is on the infrastructure assets. (This text is given as part of the scope.)

 

Reviewer 4 Report

In the abstract,

It is seen that the analysis object is the ‘terrestrial transportation infrastructure’. It would be better to include one sentence to give a brief definition or introduction about the ‘terrestrial transportation infrastructure’ because the keyword ‘‘terrestrial’ of the analysis object does not appear anywhere in the abstract.

 

In the introduction,

Firstly, the reviewer thinks that it would be more reasonable to give specific examples about the ‘extreme event’ with some literature for the authors to better understand the motivation of this work. It is recommended to briefly mention that extreme events like the earthquake [1-2], the wind load [3-4] and the corruption formulated in long-term service [5-6] may have a fatal impact on the safe operation of both the rail and road infrastructure, and even may threat the passengers’ life.

[1] Yashiro, Kazuhide, Yoshiyuki Kojima, and Mitsuru Shimizu. "Historical earthquake damage to tunnels in Japan and case studies of railway tunnels in the 2004 Niigataken-Chuetsu earthquake." Quarterly Report of RTRI 48.3 (2007): 136-141.

[2] Costa, Catarina, et al. "Application of open tools and datasets to probabilistic modeling of road traffic disruptions due to earthquake damage." Earthquake Engineering & Structural Dynamics 49.12 (2020): 1236-1255.

[3] Suangga, M., et al. "Flutter Analysis of The Sunda Strait Suspension Bridge." IOP Conference Series: Earth and Environmental Science. Vol. 794. No. 1. IOP Publishing, 2021.

[4] Song, Yang, Mingjie Zhang, Ole Øiseth, and Anders Rønnquist. "Wind deflection analysis of railway catenary under crosswind based on nonlinear finite element model and wind tunnel test." Mechanism and Machine Theory 168 (2022): 104608.

[5] Thomas, Dirk, Mats Berg, and Sebastian Stichel. "Measurements and simulations of rail vehicle dynamics with respect to overturning risk." Vehicle system dynamics 48.1 (2010): 97-112.

Secondly, normally in an introduction of a paper, the authors should indicate what is exactly the shortcoming in previous research, which may yield the novelty of this paper. In other words, the authors should point out whether this work has been done before and what their shortcomings are, instead of just presenting the report of the H2020 project SAFEWAY.

In the background,

It is a bit strange to see that the website link appears in the main body of the paper in line 112 of page 3. Normally the citation of a website link should be in the reference instead of the main body. Please modify.

What is figure 1 used for in this paper? It looks like that this figure is not mentioned anywhere in the whole texts. The quality of this paper is not very good, it look like that the texts are unnecessary extended. The symbols t0 and tt are not explained. Please modify.

In section 3,

As the railway or road transportation system is a highly coupled system, the risk normally happens in the interaction between the vehicle and the infrastructure. The reviewer is wondering how do you distinguish where do the extreme events exactly happen? If the event happens in the vehicle-infrastructure coupling interaction, has it been included in the assessment of this paper? Please clarify.

The reviewer appreciates the quantification model proposed in this paper to bridge the gap between the general risk assessment and the specific risk assessment. But one open question for the authors is how do you claim the validation of the present model? As the authors have included an example to illustrate how the proposed model works and also gave some results, how can these results be directly used by the infrastructure owner? Adding some comments on this would improve the practical value of this paper.

Author Response

Thanks a lot for valuable comments! A point-by-point response is given below:

1) In the abstract, It is seen that the analysis object is the ‘terrestrial transportation infrastructure’. It would be better to include one sentence to give a brief definition or introduction about the ‘terrestrial transportation infrastructure’ because the keyword ‘‘terrestrial’ of the analysis object does not appear anywhere in the abstract.

The term terrestrial transportation infrastructure is now included in the abstract.

2) In the introduction, Firstly, the reviewer thinks that it would be more reasonable to give specific examples about the ‘extreme event’ with some literature for the authors to better understand the motivation of this work. It is recommended to briefly mention that extreme events like the earthquake [1-2], the wind load [3-4] and the corruption formulated in long-term service [5-6] may have a fatal impact on the safe operation of both the rail and road infrastructure, and even may threat the passengers’ life.

Following this comment, we have included references per extreme event/hazard. We included references from the reference list, which addresses the effect of extreme events on terrestrial infrastructures.

3) Secondly, normally in an introduction of a paper, the authors should indicate what is exactly the shortcoming in previous research, which may yield the novelty of this paper. In other words, the authors should point out whether this work has been done before and what their shortcomings are, instead of just presenting the report of the H2020 project SAFEWAY.

The section "Risk assessment of terrestrial transportation infrastructures in literature", which presents other researchers works as well as identified gaps/shortcomings within the topic was moved to the introduction section.

4) In the background, It is a bit strange to see that the website link appears in the main body of the paper in line 112 of page 3. Normally the citation of a website link should be in the reference instead of the main body. Please modify.What is figure 1 used for in this paper? It looks like that this figure is not mentioned anywhere in the whole texts. The quality of this paper is not very good, it look like that the texts are unnecessary extended. The symbols t0 and tt are not explained. Please modify.

Based on these comments as well as comments from another reviewer, Section 2 was removed. The most relevant content of section 2 was moved to other sections, e.g. section 2.3 was moved to the introduction part.

5) In section 3, As the railway or road transportation system is a highly coupled system, the risk normally happens in the interaction between the vehicle and the infrastructure. The reviewer is wondering how do you distinguish where do the extreme events exactly happen? If the event happens in the vehicle-infrastructure coupling interaction, has it been included in the assessment of this paper? Please clarify.

The safety of the users is not considered directly, i.e., cases where road or railway users are directly injured by an extreme event are not considered and the focus is on the infrastructure assets. (This text is given as part of the scope.)

6) The reviewer appreciates the quantification model proposed in this paper to bridge the gap between the general risk assessment and the specific risk assessment. But one open question for the authors is how do you claim the validation of the present model? As the authors have included an example to illustrate how the proposed model works and also gave some results, how can these results be directly used by the infrastructure owner? Adding some comments on this would improve the practical value of this paper.

The conclusions have been extended with description on how the obtained results can be used by the infrastructure owner

Round 2

Reviewer 2 Report

The present version of the manuscript has been revised thoroughly according to the comments addressed in the first round of review.

The manuscript is now more concise, less fragmented, and significantly clearer. Nice work!

I believe that the manuscript is now ready for consideration for publication in Infrastructures.

 

This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.

Round 1

Reviewer 1 Report

The paper proposes a relevant and interesting topic, given all the episodes that happened worldwide due to climate change and the sometimes lacking response capacity. Indeed, the deep analysis and the development of a risk assessment procedure is crucial, which can serve as a decision-support tool for all the bodies responsible for the protection of people and environments.

If, on the one hand, the paper deserves attention for the topic addressed, on the other hand, it still needs improvements to be ready for publication. More specifically, I could find little correspondence between objectives and results, as I was expecting from the manuscript the definition of a theoretical and general transportation risk framework. Conversely, I could not find such a defined framework nor a strong structure of the manuscript, which I found quite confusing instead. Here below are some major and minor comments.

 

MAJOR COMMENT 1

Chapter 2 “Background” should be better arranged and further deepened, in my opinion.

First, in this chapter, a brief overview of the literature about the already existing risk assessment methods for transportation systems exposed to extreme events (or in general risk assessment methods) should be clearly provided. This is necessary to highlight the differences between the framework proposed by the authors and the ones existing in the literature. Indeed, an analysis of the gaps in the literature misses.

Moreover, the authors used a very long list of references (and only 10 are used in the intro and chap. 2), which can be used to develop the background session.

More precisely, Chapter 2.2 (and 2.2.1, 2.2.2. and 2.2.3) and 2.3 should be organized in a different manner, according to the previous observation. Also, “Risk assessment” and “Vulnerability assessment” are reported. What about “Hazard assessment”?

Second, the “Terminology” paragraph can be kept, as it briefly summarises the main definitions in the field of risk assessment and its components. This is useful as a reference reminder. However, higher consistency should be reached, both in terms of order and space dedicated to each term. More precisely, I would suggest the following improvements:

• Define a rationale behind the ordered list of the definitions (e.g., alphabetic) and declare it. This way, everything would look more systematic, and it is easier for the reader to understand and find content when coming back to this section to look for them.
• Otherwise, I would suggest listing the definitions according to a “topic” rationale, thus starting from the def. of risk and its components (hazard, vulnerability, exposure and consequences), go on with the definition of “extreme events”, “infrastructures” and “resilience”.
• For what concerns the definition of “resilience”, I would suggest putting it forehead in the introduction, being the base concept behind any risk assessment. Indeed, risk assessment tools are meant to foster the resilience of any system, by analysing the several components of risk and trying to find solutions to mitigate hazards and frequency and strengthen vulnerability. If authors want to maintain the definition of resilience in the “Terminology” paragraph, I suggest keeping just the proper definition is given at row 127, while moving row 115 to 126 elsewhere or shorting it. Indeed, this text is a long one compared to the other definitions provided and such unbalance might confuse the reader.

 

MAJOR COMMENT 2

Chapter 3 “Proposed framework for risk-assessment” is the most critical of the entire paper.

First, it does not provide any theoretical formulation of the risk assessment framework, which I was expecting instead from this paper. This chapter seems to be very confusing and not structured at all. A long list of application examples apparently follows different approaches depending on the specific extreme event considered. Just Fig.2 is provided as a draft of the general framework, but it is not sufficient.

Moreover, the authors stated that “The main focus of this paper is on the quantitative risk assessment” (row 186). In my opinion, to obtain a quantitative risk assessment some mathematical formulations should be provided, with no need for very complex formulas. At this time, no mention of formulas throughout the text is given.

Please, have a look at the following reference, which addressed the same topic (risk assessment) for a different field (road safety in public transport system) but with a structured, mathematical, and wide-applicable approach:

• https://doi.org/10.1016/j.aap.2021.106258
• https://doi.org/10.48295/ET.2021.81.4  

Also, I could not find any correspondence to the - very interesting and focused - list of questions provided in par. 2.2.1 for the general overview of risk assessment, which should be used as a baseline instead of for the new framework formulation. For instance, in rows 288-289, the authors seem to put forward the key question “What can go wrong?” while in 2.2.1 the same question is 3^rd in the list.

I would suggest rewriting the chapter completely, by developing a theoretical and general formulation of the risk assessment framework, explaining how it is built, which are the several components, how they can be computed and how are link together to get to the result. All this, by also following the questions in 2.2.1.

Fig. 2 can be further improved as a scheme of the framework and the several steps considered:

• Identification of risk scenarios and analysis scope
• Hazard assessment
• Exposure assessment
• Vulnerability assessment – structural damage and service disruption
• Consequence assessment – direct and indirect

 

In this phase, each step should be treated in the most general and theoretical way, to emphasize the wide applicability and flexibility of the framework, besides its quantitative nature.

This would give much more strength to the manuscript and would really serve as a general decision support tool for the risk assessment and mitigation, which can be flexible enough to accommodate different contexts and extreme events.

 

MAJOR COMMENT 3

All the examples and specific application references given in chapter 3, should be reported in a separate chapter (e.g., 4. Real applications), to show how the general framework can be applied to different cases and extreme events and, nonetheless, return satisfactory results.

As it is now, this long list of application case/descriptions make great confusion and does not help understand the potential of the framework, because all of them seems different (also different are the methods applied for the hazard assessment, vulnerability assessment and exposure assessment).

________________________

MINOR COMMENT 1

Paragraph 2.2.3 talks about the categorization of consequences. Given that no definition of consequence is given in the “Terminology” paragraph, I would suggest including such element in it, being a more appropriate place for the content proposed (definition and several classification types for consequences). The remaining text and all the detailed specificities can be used elsewhere, for instance in chapter 3 for the risk assessment framework development (e.g., rows 193-196 give some differences between direct and indirect consequences).

MINOR COMMENT 2

Statement at row 186 should be repeated in the objective and in the framework development description.

MINOR COMMENT 3   

I would remove the sentence reported in rows 58-60 or, at least, summarizing it in the previous description related to the objective of the project SAFEWAY.

MINOR COMMENT 4

Something seems missing from rows 71-72. Were, maybe, the authors intended to list the paper reminder? I would suggest including a brief description of all the sections/chapters of the paper besides Section 3.

MINOR COMMENT 5

Reference [3], which is related to the concept of resilience, seems not to be reported in the text at page 3. Maybe, did the authors mean [8] instead of [6] at row 142?

MINOR COMMENT 6

For what concerns bridge risk assessment, also have a look at other references.

MINOR COMMENT 7

Row 322-326 repeat what is already said before in the manuscript. I would remove it.

In what follows, I recommend other references.

• Fine, W.T., 1971. Mathematical Evaluations for Controlling Hazards. Journal of Safety Research, 3, 157-166.
• Kaplan, S., Prato, C.G., 2012. Risk factors associated with bus accident severity in the United States: A generalized ordered logit model. Journal of Safety Research, 43(3), 171-180.
• Mullai, A., 2006. Risk management system-risk assessment frameworks and techniques (Vol. 5, No. 2006). DaGoB (Safe and Reliable Transport Chains of Dangerous Goods in the Baltic Sea Region) Project Office, Turku School of Economics, Turku, Finland.

Author Response

Thank you very much for your thorough review and your effort put into this! Special thanks for your very constructive feedback, good suggestions about how to improve the paper and links to useful literature! We have started the reorganisation of the paper, by introducing a new subsection discussing gaps in literature, by splitting section 3 into 2, where the new section 3 explains how the framework is built (by asking the fundamental risk questions), how the components can be computed and mathematical formulations on how they are linked together. I think these revisions made the contribution from the work much clearer and applicable for the user. 

Unfortunately, the time for revision is very limited and we are not able to meet the deadline for submission of the revised manuscript. We will therefore resubmit the revised manuscript in October (in agreement with Pedri Zheng, our contact person for the paper)

Reviewer 2 Report

The manuscript presents a risk assessment framework for transport infrastructure. while the subject is of interest for many researchers alike there is a big question around the originality and novelty of the framework proposed in this study. the manuscript reads as an extended project proposal with some detailed reflection on different vulnerability and consequence analyses but there doesn't seem to be any contribution to current knowledge nor any reflection on how the proposed framework is different to other current-state-of-the-art studies resulted from other European projects.  the application of the framework is also limited to merely a description of how to apply this rather than a detailed analysis on a case study along with sensitivity analysis on different input parameters. 

Overall the presented manuscript does not constitute original and novel research.

Author Response

Thank you for your comments and your work on this and valuable reflections on the weaknesses of the manuscript, which we will use in the revision.

We have started the reorganisation of the manuscript and further elaboration of the framework to make the contribution from this work clearer and more applicable for the user, e.g., by introducing a new subsection discussing gaps in literature, by splitting section 3 into 2, where the new section 3 explains how the framework is built (by asking the fundamental risk questions), how the components can be computed and mathematical formulations on how they are linked together. The new section 4 describes the application examples.

Unfortunately, the time for revision is very limited and we are not able to meet the deadline for submission of the revised manuscript. We will therefore resubmit the revised manuscript in October (in agreement with Pedri Zheng, our contact person for the paper)

Reviewer 3 Report

Page 1, title “Risk assessment of terrestrial transportation systems exposed to extreme events”: My suggestion is to change the title to “Risk assessment of terrestrial transportation infrastructures exposed to extreme events”.

Page 1, Keywords: Please include “transportation infrastructures”, “natural hazard”, “vulnerability” and “resilience” in the Keywords.  

Page 1, line 24, “Efficient and secure transport networks are essential to the European society”: My suggestion is to change it to “Efficient and secure transport networks are essential worldwide”.

Page 1, Section 1. Introduction: My suggestion is to add a paragraph or two with more details concerning the H2020 project SAFEWAY.

Page 6, line 244, “…earthquakes for bridges, e.g. in [21], [22], [23], [24], [25], [26], [27], [28], [29], [30].”: Please enhance the text which is associated with the ten (10) specific references since the topic is very interesting for the reader.

Page 7, Figure 2. Framework for assessment of risk associated with extreme events on transportation systems: Please include the source of the photographs (e.g., Structural, Failure modes, Intensity, Functional).

Page 7, Section 3. Proposed framework for risk assessment: This section consists of 21 pages. It is a very interesting Section. However, I would suggest that the authors should try to divide the specific section into 2 or maybe 3 different Sections, if possible, for the benefit of the reader. For example, the case of a bridge scour in Portugal can consist of a separate “Case Study” Section.

Page 8, Table 2. Overview of failure modes/modes of malfunctioning triggered by extreme events, classified into main categories: My suggestion is to include “n.a.” (not applicable or not available) in the empty cells of the specific Table. The same comments apply in the case of other Tables with empty cells as well.

Page 10, Table 3. Rate of failure of existing bridges: Please note that the sum of the percentages in the 3^rd column is equal to 99.9% while it must be equal to 100%.

Page 13, Figure 5. Hazard presented as frequency of an event above a threshold (Here: number of days with maximum temperature above 35°C): Please try to improve the resolution of the label of the specific Figure, if it is possible.

Page 14, Figure 6. Hazard represented as intensity for a specific return period and Figure 7. Exposure of railway track to floods for different flood return periods (20-years, 100-years and 1000-years). The exposed parts of the railway are indicated with pink ellipse. I would recommend including the name of the specific geographical area in the heading of both Figures.

Page 27, Table 11. Results of risk assessment, based on assessment of all the scenarios: Please change “60-300 years” to “>60-300 years”.

Page 28, Section 4. Discussion and conclusion: My suggestion is to have a separate Section for “Discussion” and a separate Section for “Conclusion”. In the Section of Discussion, my suggestion is to investigate whether your findings comply or not with the findings of other research efforts worldwide (and if “yes”, to what extent). Please use benchmarking practice to identify similar research/case studies worldwide, if possible.  

Page 28, Section 4. Discussion and conclusion: My suggestion is to include a summary with the constraints and limitations of your work. In addition, I think that it is of high value for the paper to include a subsection dedicated to the most important policy recommendations which must be addressed to the various stakeholders (not only decision makers but also decision takers). You can use material presented in other Sections of the paper (e.g., subsection 3.4.3. on page 17) for this purpose. Finally, please be more specific concerning the future steps of the research on the topic of the paper.

 

 

Author Response

Thank you for your comments and your work on this and for fruitful suggestions for improvement of the manuscript.

We have started the reorganisation of the manuscript and further elaboration of the framework to make the contribution from this work clearer and more applicable for the user, e.g., by introducing a new subsection discussing gaps in literature, by splitting section 3 into 2, where the new section 3 explains how the framework is built (by asking the fundamental risk questions), how the components can be computed and mathematical formulations on how they are linked together. The new section 4 describes the application examples.

We have also split the section "Discussion and conclusion" into 2 separate sections and are elaboration on these, by comparing with other research efforts and addressing future steps of the research, according to your suggestions.

Unfortunately, the time for revision is very limited and we are not able to meet the deadline for submission of the revised manuscript. We will therefore resubmit the revised manuscript in October (in agreement with Pedri Zheng, our contact person for the paper)

Reviewer 4 Report

The paper is overall easy-to-follow and covers a topic that is central in the journal’s scope. A framework for risk assessment of extreme events (natural and human-made) leading to damage and/or disruptions in terrestrial transportation networks is proposed. Risk is estimated as the composition of hazard, exposure, vulnerability and consequences. The application to a case study, dealing with flooding of roadway due to exceeded culvert capacity for a generic road link, illustrates the methodology.

Despite the work is an interesting reading, the Reviewer thinks that a major revision is needed. The detailed comments are presented below:

1. The major concern is the length. The paper appears definitely too long and arranged more like a book chapter or a report than a journal paper. It includes examples of hazard or fragility assessment and takes too much space to explain/define concepts that are very well known in the scientific community working on this field, such as those of hazard, vulnerability, exposure, risk and resilience. Therefore, the Reviewer strongly suggests to substantially shorten the paper, in particular Sections 2, 3.2, 3.4, 3.5. One or more examples, which are not functional for understanding the methodology and the case study application, could be removed.
2. The current literature features many papers about the assessment of risk, as a composition of hazard, exposure and vulnerability. What are the novelties of the paper? A clear indication of advancement with respect to the available literature is actually missing and should be included.
3. Figure 10. Indication of a) and b) is missing.

Author Response

Thank you for your comments and your work on this and for valuable reflections on how the manuscript should be improved.

We have started the reorganisation of the manuscript and further elaboration of the framework to make the contribution from this work clearer and more applicable for the user, e.g., by introducing a new subsection discussing gaps in literature, by splitting section 3 into 2, where the new section 3 explains how the framework is built (by asking the fundamental risk questions), how the components can be computed and mathematical formulations on how they are linked together. The new section 4 describes the application examples. In addition, sections explaining well-known concepts will be shortened.

Unfortunately, the time for revision is very limited and we are not able to meet the deadline for submission of the revised manuscript. We will therefore resubmit the revised manuscript in October (in agreement with Pedri Zheng, our contact person for the paper)