Lessons Learnt from Bridge Collapse: A View of Sustainable Management
Round 1
Reviewer 1 Report
The article is interesting. The problem that has been raised is current and important. The result of the article was to propose guidelines for effective management of the design, construction and operation of a bridge structure. However, I have some substantive comments on this article.
Lack of a complete literature review on various methods of cause-and-effect analysis that were used to assess the technical condition of various building constructions. Fault tree analysis (FTA) method; or, for example, network Bayesian are not the only methods used. Step three to the guidelines for streamlining infrastructure management suggests management a hierarchical structure for relation between participants of project rather than structure management which is network In general, Figure 14 could be better refined because it is very important.Author Response
Reviewer #1
The article is interesting. The problem that has been raised is current and important. The result of the article was to propose guidelines for effective management of the design, construction and operation of a bridge structure. However, I have some substantive comments on this article.
Comment 1: Lack of a complete literature review on various methods of cause-and-effect analysis that were used to assess the technical condition of various building constructions. Fault tree analysis (FTA) method; or, for example, network Bayesian are not the only methods used.
Answer: Thanks for the reviewer’s valuable comment. In the revised manuscript, the introduction section has been improved by adding various methods of the cause-and-effect analysis as well as management systems, as shown in Page 2, lines 58-63 as follows:
“The existing bridge management system (BMS) includes several methods [38, 40]: (i) the grey system theory and bayesian networks; (ii) analytic hierarchy process (AHP) and fuzzy comprehensive evaluation (FCE); (iii) comprehensive evaluation based on onsite inspection. The grey system theory and bayesian networks are used to predict of bridge technical conditions [41]. AHP-FCE are used to assess the risk of the bridge damage degree or its bearing capacity [4]. The current bridge management regulations in China are mainly using comprehensive evaluation based on onsite inspection [42-55].”
Comment 2: Step three to the guidelines for streamlining infrastructure management suggests management a hierarchical structure for relation between participants of project rather than structure management, which is network. In general, Figure 14 could be better refined because it is very important.
Answer: Thanks for the reviewer’s valuable comment. The step by step procedures of management guidelines systems have been improved and the hierarchical structure in Step III has been revised as interrelated triangle structure, as shown in page 12, lines 330-334. Furthermore, Figure 14 has been improved to give a visual sense for the management and guideline for bridge and other infrastructures systems.
“hierarchical structure in Step III is revised as interrelated triangle structure. Specifically, in Step I: “Powerful and decisional supervision” is added to the fourth point; in Step II, the references about intelligent risk assessment system are added, which is shown in line 323. “Intelligent inspection procedure” is corrected as “intelligent recognition system” and it can be used for accurate and reliable post-disaster condition assessments like crack and stress concentration identification, which is shown in lines 326-329; in step III, “management network” has been reformulated as “correlative decisional management system”. The hierarchical structure is revised as interrelated triangle structure. A decisional management system with clear responsibilities consists of designer in design stage, engineer in construction stage and administrator in operational stage and supervisor during the whole periods. Each level of management has corresponding responsibilities and should take the three pillars of sustainability into consideration. It is crucial to establish correlative decisional and cooperation mechanism for the whole management, which is explained in lines 330-334; in Step IV, implemented monitoring and clear procedure for periodic maintenance make up the important part to prevent failures. Besides, detection of nonconformities and alarm system play key role in emergencies, which help establish a complete daily management system, which is explained in lines 335-338.”
Author Response File: 
Author Response.docx
Reviewer 2 Report
Dear Authors,
Thank you for the interesting manuscript with the title "Lesson Learn from Bridge Collapse: A View of Sustainable Management". Please find several comments for the improvement of the manuscript:
The newly literature source can be presented in the literature review and reference list from the 2020 year. In Figure 2 can by more presented information about the bridge collapses and casualties not only numbers. Will be great if authors in the part "Bridge failures during 2009-2019 can by presenting more exact and detail information about bridge collapses and casualties (the damage in costs or amounts or etc.); I recommended authors In Figure 3 the term "collapses number" presented in percents change and present more informative and demonstrative information. In Figure 12 In Main fault tree of Zijin Bridge collapse, the Roll-in must be presented. The used SEA methodology and presented guidelines for the bridge project can be presented in calculations together with a selected decision-making methodology and pilot practical construction project (bridge).
Reviewers
Author Response
Reviewer #2
Thank you for the interesting manuscript with the title "Lesson Learn from Bridge Collapse: A View of Sustainable Management". Please find several comments for the improvement of the manuscript:
Comment 1: The newly literature source can be presented in the literature review and reference list from the 2020 year.
Answer: Thanks for the reviewer’s valuable comment. To increase the quality of the manuscript, recent (2019, 2020) references have been cited in the revised version as follows:
Lyu, H.M., Shen, S.L., Zhou, A.N., Yang, J. Data in risk assessment of mega-city infrastructures related to land subsidence using improved trapezoidal FAHP. Data in brief 2020, 28, 105007. DOI: https://doi.org/10.1016/j.dib.2019.105007.
Ruiz, A., Guevara, J. Sustainable Decision-Making in Road Development: Analysis of Road Preservation Policies. Sustainability 2020, 12, 872; DOI: https://doi.org/10.3390/su12030872.
de Luca, S., Di Pace, R., Memoli, S., Pariota, L.. Sustainable Traffic Management in an Urban Area: An Integrated Framework for Real-Time Traffic Control and Route Guidance Design. Sustainability 2020, 12(2), 726. DOI: https://doi.org/10.3390/su12020726.
Lyu, H.M., Sun, W.J., Shen, S.L., Zhou, A.N. Risk assessment using a new consulting process in fuzzy AHP. Journal of Construction Engineering and Management 2020, 146(3), 04019112. DOI: https://doi.org/10.1061/(asce)co.1943-7862.0001757.
He, X.C., Yang, T.L., Shen, S.L., Xu, Y.S., Arulrajah, A. (2019). Land Subsidence Control Zone and Policy for the Environmental Protection of Shanghai. International Journal of Environmental Research and Public Health, 16(15), 2729; https://doi.org/10.3390/ijerph16152729.
Comment 2: In Figure 2 can by more presented information about the bridge collapses and casualties not only numbers. Will be great if authors in the part "Bridge failures during 2009-2019 can by presenting more exact and detail information about bridge collapses and casualties (the damage in costs or amounts or etc.);
Answer: Thanks for the reviewer’s valuable comment. Unfortunately, there is no available data for statistical economic loss for some collected (small-sized bridges) and bridges in remote areas. However, to give a visual sense for the changes of collapsed bridges numbers over time in the construction and service stages, Figure 2 has been added with more explanations, as shown in lines 103-111.
Comment 3: I recommended authors In Figure 3 the term "collapses number" presented in percents change and present more informative and demonstrative information.
Answer: Thanks. “Collapses number” in Figure 3 has been reformulated as “Proportion of collapsed bridges (%)”. Furthermore, more informative and effective information have been added in the revised manuscript, as shown Page 4, Lines 116-118.
Comment 4: In Figure 12 In Main fault tree of Zijin Bridge collapse, the Roll-in must be presented.
Answer: Thanks. The Roll- in has been added in Figure 12.
Comment 5: The used SEA methodology and presented guidelines for the bridge project can be presented in calculations together with a selected decision-making methodology and pilot practical construction project (bridge).
Answer: Thanks for the reviewer’s valuable comment. Markus, E. and Emmelin, L. adopted a detailed description of the decision-making process related to the Öresund Bridge using SEA and illustrated that the SEA is a good practice criteria for large-scale projects. Therefore, based on the practice of the Öresund Bridge, SEA analysis has been conducted on Zijin bridge. Furthermore, the corresponding reference has been added to the section of SEA analysis (shown in lines 70-73).
Author Response File: Author Response.docx
Reviewer 3 Report
According to the attached file.
Comments for author File: 
Comments.pdf
Author Response
Reviewer #3
Comment 1: Even if present grammar rules consider optional correct the use of comma before AND in Lists (e.g. https://www.grammarly.com/blog/comma-before-and/), the suggestion is to avoid this, unless is necessary for understanding an enumeration.
Answer: Thanks for the reviewer’s valuable comment. The manuscript has been carefully revised again and the redundant comma in lines 25, 35, 42, 49, 54 and 87 have been adjusted.
Comment 2: It is not totally correct (see the rows 119-120); not the absence of "sustainable" management was the main cause, but the underestimation of the signs of failure (= less proper expertise of people from decision positions) +/- using of bridge for economic reasons. Recommended: reformulation of phrase.
Answer: Thanks. The “sustainable management” has been reformulated as “proper expertise and sustainable concept of management layer”, which is shown in line 38;
Comment 3: It's better to change the word “worst” in line 40 to “severe”.
Answer: Thanks. The word “worst” in line 40 has been corrected as “severe”;
Comment 4: Where the “researchers” in line 50 from? Which researchers? Please add references.
Answer: Thanks. Relevant researchers have been quoted, as shown in line 50;
Comment 5: It's better to change the word “causalities” in line 40 to “associated causalities”.
Answer: Thanks. The word “causalities” has been reformulated as “associated causalities”, which is shown in line 105;
Comment 6: It's better to change the word “year” in Figure 3 to “years”.
Answer: Thanks. The word “year” in Figure 3 has been corrected as “years”;
Comment 7: It's better to add serial numbers.
Answer: Thanks. Serial numbers have been added in lines 77-80;
Comment 8: Please delete the irrelevant underline
Answer: Thanks. Irrelevant underline at line 153 has been removed;
Comment 9: NOT the bridge project is evaluated, but the bridge life/management. Ideal case: the "perfect" project design for a bridge for 100-120 years taking into account the data/ information /cases/knowledge at the moment of designing. (As scientists, we have to recognize all good things done in the past / before us).
Answer: Thanks. “bridge project” in line 220 has been corrected as “bridge management”;
Comment 10: It's better to change the word “provides” in Figure 3 to “proposes”.
Answer: Thanks. “provides” in line 222 has been corrected as “proposes”;
Comment 11a: It is not totally true for Figure 12
(1) a) if we refer to collapse of the bridge (starting with Span 3), there were cumulative factors:
- constant increasing of traffic value (row 123),
- exceeding values of river flows (rows 126-127, 183-185) and
- inadequate measures, when: i) first over-tensile signs occurred (row 118-120); ii)economical decisions prevailed (row 121); iii) extreme natural conditions occurred (row 127-129).
b) if we refer to monitoring:- even if was only regular inspection (= kind of monitoring = to observe, record or detect), in 2007 were recorded officially measures (raw 118).
Answer: Thanks for the reviewer’s valuable comment. Based on your suggestions, the basic events have been revised and Figure 12 has been modified. Arch foot failure and cumulative factors are the main causes to the collapse of Span 3. The cumulative factors are summarized as two parts: changing external circumstance and inadequate measures, which also had long-term impact on the Span 4. Changing external circumstance like constant increasing of traffic volume value and river flow value increased the traffic load and reduced the bearing capacity. Inadequate management measures include decision errors, lack of regular inspection and other management issues, which is explained in lines 249-259.
Comment 11b:
a) It is recommended do not compare two different concepts/elements without defining the criteria:- Lack of monitoring... = theoretic consideration, referring to people actions/non-actions;- ... depth of foundation = technical parameter/element, referring to a part of a construction. (e.g. It can be considered that the Pier 3 was monitored, but it was inadequate built according to the conditions/ limitations from the moment of designing, and it seems this is not the truth). For the basic event “inadequate depth of foundation” in the circular frame For what conditions?- natural?- overload / heavy transport?- illegal (but known) mining activities in the minor bed of river who induced the increasing of flow speed?- adjusted from the moment of design?
Suggestion: to eliminate the explanations from circular frames. In fact, the proposed fault tree explains the event, not the causes.
Answer: Thanks. All criteria have been defined in the revised manuscript. The former explanations from circular frames including “inadequate depth of foundation” has been removed from Figure 12 as suggested. In the revised manuscript, the newly added event such as inadequate management measures has been expressed in a circular frame to indicate the primary event, which is not in a normal or correct state. Events in roof shape frame indicate the inherent status that cannot be changed by manpower. Events in rectangular frame indicate the status that can be further analyzed.
“Pier 3 is flexible pier” is corrected as “Pier 3 was flexible pier” in Figure 12.
Comment 12: It's better to add the word “modern” between “SEA” and “practice”.
Answer: Thanks. “SEA modern practice” in line 64 has been reformulated as “SEA modern practice”;
Comment 13: Please change the upper case of link to lower case
Answer: Thanks. The word “Link” in line 278 has been corrected as “link”;
Comment 14: The construction scope of reservoirs or of bridges?
Answer: Thanks. The construction scope of infrastructures of reservoirs (near the bridge) is not well controlled, which is shown in line 283;
Comment 15: For Figure 13,
(1) is there a national norm/law that requires the daily technical inspection of each bridge, regardless of capacity? or is the capacity of the bridge regulated at daily technical inspection to be financially feasible?
(2) Any person from a technical team or level is (somehow) QUALIFIED (this does not necessarily mean having high education; but at least regular training and acceptance criteria are required). Suggestion: to eliminate complete qualified, unqualified or to include in different manner.
Answer: Thanks for the reviewer’s valuable comment. There is no national law that requires the daily technical inspection of each bridge. In Figure 13, “Daily round check” is not accurate and it has been corrected as “long-term monitoring”; “Technical level” has been reformulated as “Technical level of bridge” in Figure 13. If it qualified, the bridge will continue to be used and proceed to the next round of appraisal. If it unqualified, the bridge will be reinforced or repaired technically;
Comment 16: Please add time limit for SEA principle 2. As is mentioned early in the paper, 2007 is a VERY important moment and proved the monitoring was DONE. The measures were not perfect and long
Answer: Thanks. The second principle of SEA in Table 2 has been improved and stated as “Not perfect: Professional monitoring mechanisms after 2008”;
Comment 17: what is the subject for management guidelines in lines 324?
- bridge project /design or - bridge itself (execution and post-construction related activities)?
Answer: “Management guidelines” in line 317 has been reformulated as “Management guidelines for bridges and other infrastructures”. It refers to the execution and post-construction related activities of bridges and other infrastructures.
Comment 18: It's better to add “modern and adjusted” before “SEA” in line XX
Answer: Thanks. “SEA” in line 319 has been reformulated as “modern and adjusted SEA principles”;
Comment 19: Please delete the redundant word “core” in line 341
Answer: Thanks. The redundant word “core” has been deleted in line 335; the former sentence has been reformulated as "Adopt efficient and diversified means of prevention, which are the essence of daily management", shown in lines 335-336.
Comment 20: Step III in Figure 14 have to be re-evaluated.
(1) a) "management network" induces too many meanings (for example: we need more bosses)!
Is necessary reformulation or detailing.
b) in fact, the necessity is a correlative decisional management from design to service life (https://dictionary.cambridge.org/dictionary/english/correlative);
Answer: Thanks. “management network” in line 330 has been reformulated as “correlative decisional management system”; “hierarchical” in line 330 has been removed;
Comment 21: For Step I, Please add “decisional” between powerful and supervision; For Step II, Correlation / reference / applying of an Intelligent risk assessment system (otherwise can't be a "step" in this scheme); For step III, Policy makers are not (does not have to be!) part of the management of a technical objective. They "regulate" or decide the general frame of doing different infrastructure projects, but NOT the way of design/ construct/ life-service. Usual, an Administrator (=the one who take cares) of a bridge is named after the construction of it, so it has no hierarchical power on the designer and constructor activities. For Step IV, a correct/complete" daily management" has to include, in this order: 1) (approved, implemented) monitoring program; 2) (clear procedure for) periodic maintenance; 3) detection of nonconformities (following a regular or unscheduled inspection); 4) alarm system. (can be grouped).
Answer: Thanks for the reviewer’s valuable comment. For Figure 14, in Step I:, “Powerful and decisional supervision” has been added to the fourth point; in Step II, the references about intelligent risk assessment system have been added, which was shown in line 323. “Intelligent inspection procedure” is corrected as “intelligent recognition system” and it can be used for accurate and reliable post-disaster condition assessments like crack and stress concentration identification, which is shown in lines 326-329; in step III, “management network” has been reformulated as “correlative decisional management system”. The hierarchical structure has been revised as interrelated triangle structure. A decisional management system with clear responsibilities consists of designer in design stage, engineer in construction stage and administrator in operational stage and supervisor during the whole periods. Each level of management has corresponding responsibilities and should take the three pillars of sustainability into consideration. It is crucial to establish correlative decisional and cooperation mechanism for the whole management, which is explained in lines 330-334; in Step IV, implemented monitoring and clear procedure for periodic maintenance make up the important part to prevent failures. Besides, detection of nonconformities and alarm system play key role in emergencies, which helps to establish a complete daily management system, as shown in lines 335-338.
Comment 22: "bridge project" = design of project. However, the scheme refers more to the bridge service life...
Answer: Thanks. The title of Figure 14 is revised as “Management guidelines for bridge and other infrastructures”.
Author Response File: Author Response.docx
Round 2
Reviewer 2 Report
Dear Authors,
Thank you for the answers to the comments.
Reviewer
