Assessing flooding impact to riverine bridges: an integrated analysis

Pregnolato, Maria; Winter, Andrew O.; Mascarenas, Dakota; Sen, Andrew D.; Bates, Paul; Motley, Michael R.

doi:https://doi.org/10.5194/nhess-22-1559-2022

Articles | Volume 22, issue 5

https://doi.org/10.5194/nhess-22-1559-2022

© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

https://doi.org/10.5194/nhess-22-1559-2022

© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 22, issue 5

Research article

|

10 May 2022

Research article |

| 10 May 2022

Assessing flooding impact to riverine bridges: an integrated analysis

Maria Pregnolato, Andrew O. Winter, Dakota Mascarenas, Andrew D. Sen, Paul Bates, and Michael R. Motley

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Final revised paper (published on 10 May 2022)
Preprint (discussion started on 23 Dec 2020)

Interactive discussion

Status: closed

AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment

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- Supplement

RC1: 'Flood risk', Anonymous Referee #1, 09 Feb 2021
- AC1: 'Reply on RC1', Maria Pregnolato, 05 Apr 2021
RC2: 'Assessing flooding impact to riverine bridges', Anonymous Referee #2, 19 Feb 2021
- AC2: 'Reply on RC2', Maria Pregnolato, 05 Apr 2021

Peer-review completion

AR: Author's response | RR: Referee report | ED: Editor decision

ED: Reconsider after major revisions (further review by editor and referees) (07 Apr 2021) by Kai Schröter

AR by Maria Pregnolato on behalf of the Authors (19 May 2021) Author's response Author's tracked changes Manuscript

ED: Referee Nomination & Report Request started (19 May 2021) by Kai Schröter

RR by Anonymous Referee #3 (05 Jun 2021)

Suggestions for revision or reasons for rejection

General comment:

The paper deals with a topic of extreme interest, and correctly identifies gaps in the current literature. However, probably due to its ambition to define "a rigorous, multiphysics modelling approach for the hydrodynamic forces impacting inundated bridges, and the subsequent structural response, while understanding of the consequences of such impact on the surrounding network", it fails in its objectives and to the Reviewer's opinion appears more like a loose combination of various tools that are not well integrated together, with a not very rigorous application to a case study.
The authors are invited to substantially revise the paper, choose a more realistic case study as proof of concept, and address the following major and minor comments before this can possibly be considered for publication.

Major comments:

1. pag.7 line 211. The limitations of the proposed approach (no interaction between CFD and FE models) are not discussed. Can the bridge considered as case study be assumed as rigid for the purpose of evaluating the hydrodynamic forces, even in the case of such tall piers? Why are the piers not modeled in the computational fluid dynamic analyses?

2. pag.8 line 247. In correspondence of the M6 bridge over Carlisle, there is a large floodplain with ample opportunities for creating additional discharge. It seems very unreasonable that even under a rare-high intensity flood will be inundated.
In fact, the floodwater maximum depth for a 500yrs return period is equal to 8.424m according to Figure 3. This suggests that the deck won't be inundated.
Please consider a more realistic case study, for example one of the many masonry arch bridges that are more likely to be severely affected by floods.

3. pag. 11 line 303. The values of the lateral forces, vertical forces, and roll moments determined from OpenFOAM are not reported. Similarly, many information in the rest of the paper are missing. This is not good practice in scientific paper writing, since a journal paper should report enough data to allow results to be checked and also reproduced by others.

4. pag. 13 Line 351. If the piers and abutments are founded on rock, why is scour analysis carried out? Nevertheless, scour depths of 1-2m for foundations on piles are not a big problem.

Minor comments:

- line 325-332. The coefficient of friction between rubber and concrete is more likely to be higher than 0.4, and the assumption of a value of 0.1 seems unjustified for the assessment. Similarly, assuming that the dowels do not provide any shear resistance is too conservative.

- Why are bridge geometry and characteristics considered as exposure when they control the vulnerability and they even affect the hydraulic hazard?

- Line 257. Does "Pier width" denote "Pier height"?

- Improve caption of Figure 6.

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RR by Anonymous Referee #4 (09 Jul 2021)

ED: Reconsider after major revisions (further review by editor and referees) (12 Jul 2021) by Kai Schröter

AR by Maria Pregnolato on behalf of the Authors (23 Sep 2021) Author's response Author's tracked changes Manuscript

ED: Referee Nomination & Report Request started (01 Oct 2021) by Kai Schröter

RR by Anonymous Referee #4 (02 Oct 2021)

RR by Anonymous Referee #3 (14 Oct 2021)

Suggestions for revision or reasons for rejection

Although the authors have replied to my comments and have highlighted some of the limitations of their work in the revised manuscript, many concerns remain unsolved.

1. The scientific contribution of the paper is still unclear.
If the contribution is the development of a holistic framework for assessing susceptibility to flooding and relative consequences at systemic level, as discussed in response to the Reviewer's comments, then such a framework was already developed by others (see below a list of few).
If the novel contribution is the analysis of a realistic case study, then there are too many simplifications and there is no link between hydrological and hydraulic analysis results and too many phisically inconsistent assumptions in the fragility analysis.
The authors could select one of these topics (overarching framework, bridge fragilityanalysis under hydrodynamic loads, impact of floods on traffic redistribution, analysis of the resilience of transport infrastructure of Carlisle to flood hazard) and provide much more information on it, making clear what is the improvement of the paper with respect to the state of art.

2. I respectfully disagree with the response to comment #2. The investigated bridge has very tall piers, and from simple calculations (just assume 2 kN/m2 of hydrodynamic load) one could immediately have an idea of the potential impact of hydrodynamic loads on the pier deflection and on the top displacement demand, which is strongly related to the performance of the bearings.

3. The case study bridge has not been changed. Even under a rare event such as the one considered (500 years return period), it is not expected to be flooded. The flow velocity of 3m/s at the deck level seems high, but no actual hydraulic analysis was carried out. A more realistic scenario should be analysed.

4. Figure 6 has been added, without no explanation of the results, which are not very clear. The obtained results should be explained and discussed.

5. The assumption of a coefficient of friction of 0.1 is not justifiable. If there is uncertainty in the friction, a Monte Carlo simulation should be carried out to investigate the effect of this uncertainty, or at least a sensitivity study should be performed to investigate the effect of the assumption.

References (some of them already included in the manuscript):
- Gehl, P., & D’ayala, D. (2018). System loss assessment of bridge networks accounting for multi-hazard interactions. Structure and Infrastructure Engineering, 14(10), 1355-1371.
- Kim, B., Shin, S. C., & Kim, D. Y. (2018). Scenario-based economic impact analysis for bridge closures due to flooding: A case study of North Gyeongsang Province, South Korea. Water, 10(8), 981.
- Lamb, R., Garside, P., Pant, R., & Hall, J. W. (2019). A probabilistic model of the economic risk to Britain’s railway network from bridge scour during floods. Risk Analysis, 39(11), 2457–2478. doi:10.1111/risa.13370
- Alabbad, Y., Mount, J., Campbell, A. M., & Demir, I. (2021). Assessment of transportation system disruption and accessibility to critical amenities during flooding: Iowa case study. Science of The Total Environment, 148476.

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ED: Reconsider after major revisions (further review by editor and referees) (18 Oct 2021) by Kai Schröter

AR by Maria Pregnolato on behalf of the Authors (12 Jan 2022) Author's response Author's tracked changes

ED: Referee Nomination & Report Request started (14 Jan 2022) by Kai Schröter

RR by Anonymous Referee #3 (25 Jan 2022)

ED: Publish subject to minor revisions (review by editor) (14 Mar 2022) by Kai Schröter

AR by Maria Pregnolato on behalf of the Authors (22 Mar 2022) Author's response Author's tracked changes Manuscript

ED: Publish subject to technical corrections (24 Mar 2022) by Kai Schröter

AR by Maria Pregnolato on behalf of the Authors (01 Apr 2022) Author's response Manuscript

Short summary

The interaction of flow, structure and network is complex, and yet to be fully understood. This study aims to establish rigorous practices of computational fluid dynamics (CFD) for modelling hydrodynamic forces on inundated bridges, and understanding the consequences of such impacts on the surrounding network. The objectives of this study are to model hydrodynamic forces as the demand on the bridge structure, to advance a structural reliability and network-level analysis.