Post-Earthquake Fire Resistance in Structures: A Review of Current Research and Future Directions

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The paper provides a comprehensive review of post-earthquake fires (PEFs), a critical secondary hazard in earthquake-prone regions. It highlights the challenges posed by the interplay between seismic damage and fire resistance. The emphasis on ignition sources, structural vulnerabilities, and performance-based design approaches is a valuable contribution to the field. However, several areas require improvement to enhance the clarity and impact of the work.

1. Analysis of PEF Scenarios:

   • The paper lacks a structured methodology for conducting PEF analyses. A clear framework, potentially supported by flowcharts or conceptual maps, would guide readers in understanding how to approach such assessments.
   • How should researchers and practitioners systematically account for the sequence of events from seismic damage to fire ignition and propagation?
   • The integration of sequential analysis steps, including damage assessment, ignition potential, and fire resistance evaluation, should be more clearly outlined.

2. Statistical Data:

   • The review mentions the need for enhanced data collection but does not present or discuss existing statistical datasets on PEF events.
   • Incorporating historical PEF data, including ignition rates and structural failure statistics, would provide a more evidence-based foundation for the findings.
   • How can probabilistic risk assessments be refined using such data, and what specific data sources should be prioritised for collection?

3. Innovation and Contributions:

   • The paper does not clearly articulate how the findings advance the current state of the art.
   • What specific innovations do the authors propose to improve PEF assessment and mitigation?
   • How do these innovations benefit the research community and practical applications in building design?
   • Including examples of potential technological advancements or novel design strategies would strengthen the paper's contribution.

4. Practical Implications and Guidelines:

   • While the need for integrating PEF considerations into building codes is acknowledged, the paper does not provide concrete suggestions on how this integration could be achieved.
   • What specific recommendations can be made for incorporating PEF scenarios into performance-based design guidelines?
   • Including case studies or proposed framework elements would provide valuable insights for practitioners.

By addressing these gaps and providing a clearer methodology, supported by statistical data and innovative contributions, the paper would significantly improve its relevance and impact on the research and engineering community.

Comments for author File: Comments.pdf

Author Response

Comments 1: The paper lacks a structured methodology for conducting PEF analyses. A clear framework, potentially supported by flowcharts or conceptual maps, would guide readers in understanding how to approach such assessments.
How should researchers and practitioners systematically account for the sequence of events from seismic damage to fire ignition and propagation?
The integration of sequential analysis steps, including damage assessment, ignition potential, and fire resistance evaluation, should be more clearly outlined.

Response 1: A structured methodology has been incorporated into the paper, addressing the reviewer's comments by clearly outlining the sequential analysis steps, including damage assessment, ignition potential, and fire resistance evaluation.

Comments 2: The review mentions the need for enhanced data collection but does not present or discuss existing statistical datasets on PEF events.
Incorporating historical PEF data, including ignition rates and structural failure statistics, would provide a more evidence-based foundation for the findings.
How can probabilistic risk assessments be refined using such data, and what specific data sources should be prioritized for collection?

Response 2: A section providing a historical overview of PEF events has been added to the paper. However, the incorporation of historical PEF data and the refinement of probabilistic risk assessments were initially part of a detailed discussion on design strategies and their integration with design codes. Since this aspect was kept out of the scope of the current paper, it will be explored further in future studies.

Comments 3: The paper does not clearly articulate how the findings advance the current state of the art.
What specific innovations do the authors propose to improve PEF assessment and mitigation?
How do these innovations benefit the research community and practical applications in building design?
Including examples of potential technological advancements or novel design strategies would strengthen the paper's contribution.

Response 3: As mentioned in previous responses, the primary objective of this paper is to provide an overview of existing research on PEF and identify current gaps in the field. While this study highlights areas that require further investigation, a more detailed exploration of innovations and novel design strategies will be the focus of future research by the authors.

Comments 4: While the need for integrating PEF considerations into building codes is acknowledged, the paper does not provide concrete suggestions on how this integration could be achieved.
What specific recommendations can be made for incorporating PEF scenarios into performance-based design guidelines?
Including case studies or proposed framework elements would provide valuable insights for practitioners.

Response 4: The authors have provided suggestions for future research in Section 10 (Future Research Needs and Potential Directions for Advancement in PEF Engineering). We would appreciate any specific topics the reviewer recommends addressing to further enhance this discussion.

Reviewer 2 Report

Comments and Suggestions for Authors

The manuscript is highly detailed and well-structured, effectively covering the key aspects of post-earthquake fire (PEF) and its implications for structural integrity. However, several areas could benefit from improvement:

1. Figure 1: This figure is not referenced in the text. It is important to mention all figures within the text to provide context for the reader.

2. Line 203: The abbreviations “CFS-F” and “CFS-C” should be explained. Please clarify what these abbreviations stand for.

3. Line 237: Additional information on the steel grade "Q345" is needed. Consider including details such as its composition, mechanical properties, and why it is relevant to the study.

4. Conclusions Section: The conclusions should be presented in separate points or paragraphs rather than as a single block of text. This will improve readability and make each conclusion more distinct.

Comments on the Quality of English Language

Some sentences are overly complex, which may reduce clarity. Breaking them down into shorter sentences will enhance readability.

Author Response

Comments 1: Figure 1: This figure is not referenced in the text. It is important to mention all figures within the text to provide context for the reader.

Response 1: Thank you for pointing this out. We agree with this comment. Therefore, we have removed Figure 1 from the manuscript to address potential copyright concerns.

Comments 2: Line 203: The abbreviations “CFS-F” and “CFS-C” should be explained. Please clarify what these abbreviations stand for.

Response 2: Thank you for your suggestion. We have added the explanations for “CFS-F” and “CFS-C” in the relevant section of the manuscript.

Comments 3: Line 237: Additional information on the steel grade "Q345" is needed. Consider including details such as its composition, mechanical properties, and why it is relevant to the study.

Response 3: We appreciate this valuable comment. The required details regarding the composition, mechanical properties, and significance of steel grade "Q345" have been incorporated into the relevant section of the manuscript.

 

Comments 4: Conclusions Section: The conclusions should be presented in separate points or paragraphs rather than as a single block of text. This will improve readability and make each conclusion more distinct.

Response 4: We have revised the Conclusions section to present the key points in separate paragraphs, enhancing readability and clarity.

Reviewer 3 Report

Comments and Suggestions for Authors

This review paper provides a comprehensive synthesis of current research on post-earthquake fire (PEF) resistance in structural systems, addressing the critical interplay between seismic damage and subsequent fire hazards. The authors successfully highlight key challenges (e.g., data scarcity, oversimplified models) and propose future directions for multi-hazard design frameworks. The manuscript is well-structured and aligns with the scope of Applied Sciences.

Minor comments:

1. The paper should provide emerging trends, such as machine learning applications in PEF risk prediction.

2. Equations (2) and (3) lack definitions for critical parameters, hindering reproducibility.

3. Include a flowchart illustrating the proposed "multi-hazard design paradigm."

4. While the literature review is extensive, it lacks depth in evaluating conflicting findings or methodological limitations. For example, Section 5.6 (CFST columns) does not address discrepancies in fire resistance predictions between experimental and numerical studies.

5. The paper lacks a comparative framework to evaluate the effectiveness of different design strategies (e.g., performance-based design vs. prescriptive codes) in mitigating PEF risks.

6. It is recommended to add a subsection in Section 6 discussing the capabilities and limitations of existing computational tools for PEF analysis.

Author Response

Comments 1: The paper should provide emerging trends, such as machine learning applications in PEF risk prediction.

Response 1: While this paper aims to provide a comprehensive overview of post-earthquake fire (PEF), the broad scope of the topic makes it challenging to cover all aspects in detail. The suggested topic of machine learning applications in PEF risk prediction is valuable and will be considered for future research.

Comments 2: Equations (2) and (3) lack definitions for critical parameters, hindering reproducibility.

Response 2: Definitions for the mentioned parameters have been added to the relevant section to enhance clarity and reproducibility.

Comments 3: Include a flowchart illustrating the proposed "multi-hazard design paradigm."

Response 3: A section has been added to the paper outlining the structural methodology of PEF assessment, along with an illustration to enhance clarity.

Comments 4: While the literature review is extensive, it lacks depth in evaluating conflicting findings or methodological limitations. For example, Section 5.6 (CFST columns) does not address discrepancies in fire resistance predictions between experimental and numerical studies.

Response 4: The authors have aimed to provide a broad overview of existing studies while identifying key research gaps in Section 10 (Future Research Needs and Potential Directions for Advancement in PEF Engineering). Given the wide scope of the topic, an in-depth analysis of each specific aspect, including discrepancies in fire resistance predictions, will be the focus of future research.

Comments 5: The paper lacks a comparative framework to evaluate the effectiveness of different design strategies (e.g., performance-based design vs. prescriptive codes) in mitigating PEF risks.

Response 5: An initial version of the paper included a detailed section on design strategies. However, the authors decided to keep this aspect outside the scope of the current study and instead dedicate a separate, in-depth research work to exploring these strategies and their integration with design codes.

Comments 6: It is recommended to add a subsection in Section 6 discussing the capabilities and limitations of existing computational tools for PEF analysis.

Response 6: As mentioned in Response 5, the authors have decided to keep the discussion on computational tools outside the scope of this paper to maintain focus and conciseness. This topic will be explored in a separate, more detailed study.

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

The article provides a comprehensive and well-structured review of post-earthquake fires (PEFs), effectively addressing the interplay between seismic damage and fire resistance. It thoroughly examines ignition sources, cascading structural effects, and advanced performance-based design approaches, including probabilistic risk assessments, sequential analysis, and hybrid fire simulations.

Key findings are clearly articulated, highlighting the significant impact of seismic damage such as spalling, cracking, and fireproofing loss on the fire resistance of steel and reinforced concrete structures. The discussion effectively underscores existing research gaps, particularly in experimental data, probabilistic modelling, and performance-based design guidelines, while also proposing practical solutions to address these challenges.

The study successfully integrates the need for enhanced data collection, improved modelling techniques, and the incorporation of PEF considerations into building codes, reinforcing the importance of a holistic, multi-hazard design approach. The conclusions are well-founded and provide valuable insights for both future research and practical applications aimed at mitigating the compounded effects of earthquakes and fires.

Finally, the article meets all the requirements set forth by the reviewer, offering a rigorous and insightful analysis that contributes significantly to the field of structural resilience in multi-hazard scenarios.