Probability Assessment of the Seismic Risk of Highway Bridges with Various Structural Systems (Case Study: Tehran City)
Round 1
Reviewer 1 Report
This manuscript takes 713 bridges in Tehran as the object. Through the Optimized Probability Scenario (OPS) algorithm, a set of 50 ground motion records was selected during the probability method process, attempting to obtain the minimum error compared to the original catalog in the final danger curve of different regions in Tehran. Afterwards, based on the brittleness of the earthquake, the curves of six bridge structural systems, namely simply supported, steel structures, concrete slab boxes, concrete slab steel box beams, concrete slabs, and steel beam concrete slabs, were drawn under four damage states: mild, moderate, extensive, and complete. The results of the vulnerability curve extracted from decision tree analysis and the results developed from Incremental Dynamic Analysis (IDA) were validated in a bridge case study modeled in OpenSEES software. Finally, using some logical relationships, seismic risk curves were plotted for each structural system. However, there are still some issues that need to be revised in the paper. The specific opinions are as follows:
1.Please adjust the format of the full text, such as the alignment of tables and figures.
2.What is the reference basis for setting the earthquake disaster with a reconstruction period of 475 years (10% within 50 years) as the benchmark？
3.In this paper, 20 records are selected from Peer and Iran databases for input. Please provide the data table of the selected records to make the conclusion more reliable.
4.It can briefly explain the principle of the software prepared in the paper defining shear wave velocity in the form of partitioned contour lines or discrete points (which can perform three-dimensional interpolation to calculate shear wave velocity at any desired point). To facilitate the reader's understanding
5.Figures 7, 8, 15, and 16 of the paper indicate that the size of PGA is not obvious with the size of a circle and the depth of the same color. It is recommended to use different shapes or colors to distinguish.
6.The description of the research process in the conclusion part is not concise enough, please revise it, and make a proper summary of the deficiencies of the research or the content worth further research.
7.The references in the recent 3 years is insufficient, please supplement appropriately to understand the latest research.
Some English expression of the manuscript needs to be modified. The language still needs to be further refined.
Author Response
Comments and Suggestions for Authors
This manuscript takes 713 bridges in Tehran as the object. Through the Optimized Probability Scenario (OPS) algorithm, a set of 50 ground motion records was selected during the probability method process, attempting to obtain the minimum error compared to the original catalog in the final danger curve of different regions in Tehran. Afterwards, based on the brittleness of the earthquake, the curves of six bridge structural systems, namely simply supported, steel structures, concrete slab boxes, concrete slab steel box beams, concrete slabs, and steel beam concrete slabs, were drawn under four damage states: mild, moderate, extensive, and complete. The results of the vulnerability curve extracted from decision tree analysis and the results developed from Incremental Dynamic Analysis (IDA) were validated in a bridge case study modeled in OpenSEES software. Finally, using some logical relationships, seismic risk curves were plotted for each structural system. However, there are still some issues that need to be revised in the paper. The specific opinions are as follows:
Thanks to the respected referee who mentioned useful points by carefully reading the article. In the future, it was tried to eliminate the ambiguities and defects by making the necessary reforms.
Point 1: Please adjust the format of the full text, such as the alignment of tables and figures.
Response 1: Changes have been made in the paper based on the comment.
Point 2: What is the reference basis for setting the earthquake disaster with a reconstruction period of 475 years (10% within 50 years) as the benchmark？
Response 2: This matter was stated correctly and was corrected and explained in the article based on synthetic earthquake catalogues representing long term seismicity and attenuation functions are used to model probabilistic strong ground motions impacting bridges. Each earthquake scenario results in probabilistic and spatial distributions of damages to bridges in Tehran province.
Point 3: In this paper, 20 records are selected from Peer and Iran databases for input. Please provide the data table of the selected records to make the conclusion more reliable.
Response 3: 20 earthquake records suggested by Naseri et al. [40] were used to verify the results, of which 16 records were suggested by FEMA P695 and 4 records were downloaded from Pir's site according to the type of soil and structure. The table of selected records is as follows, which was added in the revised article.
Earthquake records used in the analysis [40]
|
PGA max (g) |
NEHRP Class |
Station Name |
Earthquake |
ID NO. |
||
|
Name |
Year |
M |
||||
|
0.52 |
D |
Beverly Hills - Mulhol |
Northridge |
1994 |
6.7 |
R1 |
|
0.48 |
D |
Canyon Country-WLC |
Northridge |
1994 |
6.7 |
R2 |
|
0.82 |
D |
Bolu |
Duzce, Turkey |
1999 |
7.1 |
R3 |
|
0.334 |
D |
WGK |
Chi-Chi, Taiwan |
1999 |
7.6 |
R4 |
|
0.35 |
D |
Delta |
Imperial Valley |
1979 |
6.5 |
R5 |
|
0.38 |
D |
El Centro Array #11 |
Imperial Valley |
1979 |
6.5 |
R6 |
|
0.506 |
D |
6619 SAHOP Casa Flores |
Imperial Valley |
1979 |
6.5 |
R7 |
|
0.24 |
D |
Shin-Osaka |
Kobe, Japan |
1995 |
6.9 |
R8 |
|
0.36 |
D |
Duzce |
Kocaeli, Turkey |
1999 |
7.5 |
R9 |
|
0.108 |
D |
71 Ferdows |
Tabas, Iran |
1978 |
7.4 |
R10 |
|
0.24 |
D |
Yermo Fire Station |
Landers |
199 |
7.3 |
R11 |
|
0.42 |
D |
Coolwater |
Landers |
199 |
7.3 |
R12 |
|
0.53 |
D |
Capitola |
Loma Prieta |
198 |
6.9 |
R13 |
|
0.56 |
D |
Gilroy Array #3 |
Loma Prieta |
1989 |
6.9 |
R14 |
|
0.11 |
D |
BHRC Tonekabun |
Manjil, Iran |
1990 |
7.4 |
R15 |
|
0.36 |
D |
El Centro Imp. Co. |
Superstition Hills |
1987 |
6.5 |
R16 |
|
0.45 |
D |
Poe Road (temp) |
Superstition Hills |
1987 |
6.5 |
R17 |
|
0.55 |
D |
Rio Dell Overpass |
Cape Mendocino |
1992 |
7.0 |
R18 |
|
0.44 |
D |
CHY101 |
Chi-Chi, Taiwan |
1999 |
7.6 |
R19 |
|
0.21 |
D |
LA - Hollywood Stor |
San Fernando |
1971 |
6.6 |
R20 |
Point 4: It can briefly explain the principle of the software prepared in the paper defining shear wave velocity in the form of partitioned contour lines or discrete points (which can perform three-dimensional interpolation to calculate shear wave velocity at any desired point). To facilitate the reader's understanding.
Response 4: Using the points where the shear wave velocity is available (based on geographical coordinates), the value of the shear wave velocity for any arbitrary point is calculated using the linear IDW method. The linear interpolation method using IDW (Inverse Distance Weighting) is a common method in geophysics that is used to estimate data values at points where measurements have not been made. Regarding the soil shear wave velocity, this method can help to estimate and visualize the soil shear wave velocity pattern in areas where direct measurement data are not available. In the IDW method, it is assumed that the nearest neighbors of the desired point have the greatest influence on it. Based on this assumption, the value at each point is estimated according to its distance with the existing data points and the weight that is calculated based on that distance.
The general equation of IDW is as follows:
(5)
Z(x) represents the value at the point x that you want to interpolate.
Zi represents the value at data point i.
wi(x) is the weight corresponding to data point i at point x, which is calculated based on its distance from point x. This weight is usually the inverse of the distance to the second power of the inverse of the distance
Point 5: Figures 7, 8, 15, and 16 of the paper indicate that the size of PGA is not obvious with the size of a circle and the depth of the same color. It is recommended to use different shapes or colors to distinguish.
Response 5: As shown in figures 7, 8, 15 and 16, the dimensions of the circles as well as their color according to the PGA values are drawn in the side part of each figure. For example, Figure 8 is shown below.
Figure 8. Acceleration in bridges, subjected to record No. 10 (magnitude of 5.4 on the Richter scale).
Point 6: The description of the research process in the conclusion part is not concise enough, please revise it, and make a proper summary of the deficiencies of the research or the content worth further research.
Response 6: The conclusion part of the article was modified according to the comments of the honorable referee.
Point 7: The references in the recent 3 years is insufficient, please supplement appropriately to understand the latest research.
Response 7: References of the last 3 years were added in the submitted article.
Point 8: Comments on the Quality of English Language, Some English expression of the manuscript needs to be modified. The language still needs to be further refined.
Response 8: The submitted article was completely revised and all corrections were made in the English language.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
This paper introduced “Probability assessment of seismic risk of highway bridges with various structural systems (Case Study: Tehran City)”. The reviewer believes that this work is useful for engineering applications. However, necessary modifications and clarifications to the manuscript are necessary before it can be considered after the corrections suggested below:
1. The authors provide background in the Introduction section. However, there is no reference to confirm the information. Please the authors provide references in the introduction.
2. Literature review section should be part of the introduction. Please the authors combine the “Introduction and Literature review” in the current version to be one section “Introduction”. In addition, please the authors double-check the reference style in the main text.
3. The authors mentions that use the Opensee to perform analysis. Please authors provide more detail information for the analysis models.
4. Please the authors provide the reason for selecting the example of the bridges to perform the analysis.
5. Each equation should be updated their formant.
6. The authors presents the results in Figure 10. However, the detail discussion and comparison do not provide appropriately although the authors provide the reference [64] under the Figure 10. Please the authors provide more information, discussion and comparison for provided results, especially the Figure 10.
7. Please the authors the number of ground motions to investigate the damage of the bridges. Meanwhile, please the authors clearly the specification or code, which the authors use for referring the selection of ground motion such as ASCE7 or other international specifications.
8. Please the authors confirm the Conclusions after modifications and clarifications to the manuscript. The reviewer suggests that the Conclusion section should be pointed each outcome separately.
Minor editing of English language required. The reviewer would recommend having it proofread by a native speaker or carefully checking.
Author Response
Dear Reviewer 2
Thank you so much for reviewing the paper meticulously and making valuable comments to help improve its quality. We have provided a list of responses to the comments given below. The changes have been made to the revised manuscript.
Best regards,
Sincerely,
Hamid Reza Tavakoli
Assoc. Prof, Faculty of Civil Engineering, Babol Noshirvani University of Technology, Babol, Iran,
Email: [email protected]
Author Response File: Author Response.pdf
Reviewer 3 Report
The authors presented a very interesting piece of work entitled “Probability assessment of seismic risk of highway bridges with various systems (Case Study: Tehran City)”. The authors are encouraged to revise the manuscript following the comments:
1) Please mention units for all variables used in the equations in the paper. Even if any variable is unitless, please mention so.
2) Please explain how the Google Maps API was applied. How does it work? Provide details.
3) Page no. 6, Line 213-214: How did authors determine the population living near the bridges? How about checking the traffic volume over the bridges instead of determining the population?
4) Figure 2 and Figure 3: Please cite the paper using style [11].
5) Almost all figures have poor quality and difficult to read. Please improve the quality of figures in the paper.
6) Page no. 19, Line 412: What are the possible reasons for this difference between model (1) and model (2) fragility curve results?
7) Page no. 25, Line 476-478: From structure viewpoint, what are the reasons for this kind of order/behavior (which is also shown in Figure 23)?
8) The non-engineering defects during the construction phase of a structure are also responsible for the major damages under seismic forces. Such kind of study was also conducted by Javed et al. (2023) to quantify the severity of high-risk structural systems due to non-engineering defects through experiment using shake table. To strengthen the Literature Review, the authors are encouraged to also cite this research:
Javed, A., Krishna, C., Ali, K., Afzal, M. F. U. D., Mehrabi, A., & Meguro, K. (2023). Micro-Scale Experimental Approach for the Seismic Performance Evaluation of RC Frames with Improper Lap Splices. Infrastructures, 8(3), 56.
Page no. 14, Line 332, "is" will be replaced by "are". Please also check entire manuscript for removing typing errors and other mistakes
Author Response
Dear Reviewer 3
Thank you so much for reviewing the paper meticulously and making valuable comments to help improve its quality. We have provided a list of responses to the comments given below. The changes have been made to the revised manuscript.
Best regards,
Sincerely,
Hamid Reza Tavakoli
Assoc. Prof, Faculty of Civil Engineering, Babol Noshirvani University of Technology, Babol, Iran,
Email: [email protected]
Author Response File: Author Response.pdf
Reviewer 4 Report
The manuscript deals with the seismic risk assessment of existing bridges in the Tehran region. According to this reviewer’s opinion, the manuscript is very difficult to understand and require extensive clarifications in methodology, structure, figures and equations. Comments are provided below.
The abstract includes preliminary results which require clarifications (e.g. “The results indicate that, in all cases, median vulnerability decreases by an average of 0.88 with increasing the age of bridge.”, what 0.88 is referred to?)
According to this reviewer’s opinion, the structure of the manuscript is confusing. This reviewer suggests grouping the sections based on “Methodology”, “Case-study application” and/or “Results”.
The state-of-the-art requires extensions. References to studies aimed at computing fragility curves for bridges via numerical approaches are presented. However, additional studies on computing fragility curves via empirical or simplified methods, which can be particularly useful for large-scale risk assessment, should be included (10.1016/j.engstruct.2021.113832, 10.1007/s10518-020-00861-9).
L172 does A refer to the unitary cost? Please clarify.
Please provide clarifications on how the coefficients P (reconstruction time) ad I (importance) for indirect loss calculation and list suitable references if existing. (e.g. in which way is the normalisation carried out). Instructions for computing the coefficient I are completely absent. What does CON quantify?
How are ground motion fields in figure 5 computed? Are Ground Motion Prediction Equations used?
Why do the authors use only the fault zone presented in Figure 6?
Do the fragility curves listed in Table 9 use different intensity measures? If yes, how are different IM managed?
In several parts of the manuscript, the authors refer to “decision tree”. Decision tree are techniques to address decision based on subsequent tests. How is this technique used in this study?
The author should explain how the increasing of fragility after 10 years of service life is modelled in Figure 10.
The methodology for computing damage state in section 15 is not clear and requires explanations. Additionally, damage-to-loss ratios (Section 16) adopted are different than literature studies (Federal Emergency Management Agency (FEMA), “Hazus Earthquake Model Technical Manual - Hazus 5.1. 2022.). Indeed, generally, a loss ratio equal to 100% is assigned to complete damage. How the damage-to-loss ratios adopted in this study are computed?
All the components included in Equations requires explanations in the text (e.g. equation 6 is not explained).
Moderate corrections in terminology are required.
Author Response
Dear Reviewer 4
Thank you so much for reviewing the paper meticulously and making valuable comments to help improve its quality. We have provided a list of responses to the comments given below. The changes have been made to the revised manuscript.
Best regards,
Sincerely,
Hamid Reza Tavakoli
Assoc. Prof, Faculty of Civil Engineering, Babol Noshirvani University of Technology, Babol, Iran,
Email: [email protected]
Author Response File: Author Response.pdf
Round 2
Reviewer 2 Report
Dear Author,
This paper introduced “Probability assessment of seismic risk of highway bridges with various structural systems (Case Study: Tehran City)”. The reviewer believes that this work is useful for engineering applications. The author have tried to improve the quality of the paper based on the reviewer's suggestion.
Minor editing of English language required
Author Response
Comments and Suggestions (Reviewer# 2) for Authors
Dear Author,
This paper introduced “Probability assessment of seismic risk of highway bridges with various structural systems (Case Study: Tehran City)”. The reviewer believes that this work is useful for engineering applications. The authors have tried to improve the quality of the paper based on the reviewer's suggestion.
Comments on the Quality of English Language: Minor editing of English language required
It was revised and corrected with a minor revision in the article.
Author Response File: Author Response.pdf
Reviewer 4 Report
1) This reviewer is not able to find modifications/revisions with respect to the original manuscript for the reviewer’s considerations numbered as point 2, 3, 4, 5, 6 7, 11 (according to the authors’note). Please, provide extracts of the applied modifications in the authors’ note to make easier the review process.
Please address such comments by modifying the manuscript or, alternatively, provide adequate responses for not addressing the reviewer’s observations.
2) Please add a description of the so called “decision tree” (point 9 of the previous review) in this manuscript. Although the method is commented in other authors’ studies, an appropriate explanation is essential for readers interested in understanding the presented manuscipt.
3) Do references exist for the coefficient C which models the increase in fragility after 10 year for a given bridge?
Additional corrections in terminology and language are required.
Author Response
Comments and Suggestions for Authors
The manuscript deals with the seismic risk assessment of existing bridges in the Tehran region. According to this reviewer’s opinion, the manuscript is very difficult to understand and require extensive clarifications in methodology, structure, figures and equations. Comments are provided below.
Thanks to the respected referee who took time for the article and read the article. It is hoped that it will be improved by removing the ambiguities and making corrections to the article.
Point 2: According to this reviewer’s opinion, the structure of the manuscript is confusing. This reviewer suggests grouping the sections based on “Methodology”, “Case-study application” and/or “Results”.
Response 2: The generalities of the article are in these four sections, but due to the fact that the topic is more clear and the categories are used more titles.
- Section 1 , 2 : Introduction
- Section 3,4,5,6,7,8,9 : Methodology
- Section 10,11,12,13 : Case-study application
- Section 14,15,16 : Results
- Setion 17 : Conclusions
Point 3: The state-of-the-art requires extensions. References to studies aimed at computing fragility curves for bridges via numerical approaches are presented. However, additional studies on computing fragility curves via empirical or simplified methods, which can be particularly useful for large-scale risk assessment, should be included (The state-of-the-art requires extensions. References to studies aimed at computing fragility curves for bridges via numerical approaches are presented. However, additional studies on computing fragility curves via empirical or simplified methods, which can be particularly useful for large-scale risk assessment, should be included (10.1016/j.engstruct.2021.113832, 10.1007/s10518-020-00861-9).
Response 3: It was added and referenced to the article.
Point 4: L172 does A refer to the unitary cost? Please clarify.
Response 4: The coefficient a is actually the ratio of costs required to build a unit of concrete bridge length, which is different for bridges with different systems. In order not to limit this cost, the monetary unit for it is not stated in the article and it is mentioned relatively for different bridge systems.
Point 5: Please provide clarifications on how the coefficients P (reconstruction time) ad I (importance) for indirect loss calculation and list suitable references if existing. (e.g. in which way is the normalisation carried out). Instructions for computing the coefficient I are completely absent. What does CON quantify?
Response 5: Explained in the article.
Point 6: How are ground motion fields in figure 5 computed? Are Ground Motion Prediction Equations used?
Response 6: Based on a synthetic earthquake catalog representing long-term seismicity and attenuation functions, it is used for probabilistic modeling of strong ground motions of impact bridges, which was explained in the article, and referenced.
Point 7: Why do the authors use only the fault zone presented in Figure 6?
Response 7: Explanations on how to use were added to the article
Point 9: In several parts of the manuscript, the authors refer to “decision tree”. Decision tree are techniques to address decision based on subsequent tests. How is this technique used in this study?
Response 9: This case is fully described in reference 67, which is an article by the same author, and its results are also used in this article.
Point 11: The methodology for computing damage state in w1section 15 is not clear and requires explanations. Additionally, damage-to-loss ratios (Section 16) adopted are different than literature studies (Federal Emergency Management Agency (FEMA), “Hazus Earthquake Model Technical Manual - Hazus 5.1. 2022.). Indeed, generally, a loss ratio equal to 100% is assigned to complete damage. How the damage-to-loss ratios adopted in this study are computed?
Response 11: With a fairly correct assumption and close to reality that as the failure mode tends to increase from slight to complete, the risk will also increase from slight to complete, and for faster analysis of the introduced algorithm with an engineering judgment, these numbers have been introduced, which are not far from the fact and in modeling Expanded or the program was developed, these numbers can be changed for more accuracy.
1) This reviewer is not able to find modifications/revisions with respect to the original manuscript for the reviewer’s considerations numbered as point 2, 3, 4, 5, 6, 7, 11 (according to the authors’note). Please, provide extracts of the applied modifications in the authors’ note to make easier the review process.
Please address such comments by modifying the manuscript or, alternatively, provide adequate responses for not addressing the reviewer’s observations.
2) Please add a description of the so called “decision tree” (point 9 of the previous review) in this manuscript. Although the method is commented in other authors’ studies, an appropriate explanation is essential for readers interested in understanding the presented manuscipt.
Response 9: This case is fully described in reference 67, which is an article by the same author, and its results are also used in this article. Please read that article.
3) Do references exist for the coefficient C which models the increase in fragility after 10 year for a given bridge?
As stated in the article, the coefficient c was considered as an engineering judgment in this article:
Coefficient C denotes the life of the structure. Obviously, the older the bridge structure is, the less financial value it has. However, the amount of financial loss will be less in the case of earthquake and damage occurrence. In order to apply this parameter, the structures were divided into two classes of old and new, and the values of coefficient C for each class were proposed according to Table 4.
Table 4. Values of coefficient C according to the age of bridge structure.
|
Coefficient C |
Bridge age |
|
1 |
Equal or less than 10 years |
|
0.9 |
More than 10 years |
It is, however, worth noticing that the proposed relationships and the coefficients were obtained based on the engineering points of view. Nevertheless, one can use the real value of an existing bridge in the modeling if the real value of that bridge is available.
4) Comments on the Quality of English Language:
Additional corrections in terminology and language are required.
Response 4: It was revised and corrected with a minor revision in the article.
Author Response File: Author Response.pdf
Round 3
Reviewer 4 Report
None
None
