A Simplified Framework for Historic Cities to Define Strategies Aimed at Implementing Resilience Skills: The Case of Lisbon Downtown

Round 1

Reviewer 1 Report

The case study suggests the development of a framework for studying historic cities to identify methods for implementing resilience capacities in Lisbon's centre. The research provided is fascinating, well-organized, and provides empirical information on the seismic vulnerability of the Lisbon structure. Although the article utilises non-innovative methodologies, it is exhaustive from a technical perspective. Kindly be informed of the minor changes listed below before proceeding with publication:

Q1: What is the meaning of "Identification of an analysis methodology […]" if the authors then use only 2 types of analysis? Please modify; Moreover, What are the reasons for choosing methods based on the vulnerability index over others?

Q2: It would be interesting to understand how the calibrations were performed concerning paragraph 2.2. The authors are requested to give more elucidations regarding the data used for the calibrations;

Q3: In equation 1, did the authors take into account the regional modifier? Specify how;

Q4: The authors in Tables 4, 5 and 6 show the results regarding the loss estimation. If so, are these matrices based on predictive analytics? What is the theory behind the quantification of losses? More clarifications are required;

Q5: The values proposed for the calculation of equation 5 should be validated based on European data. What do the authors suggest in this regard?

Q6: What is the innovative aspect of the proposed research and what contribution does it make? What are the limitations of the applied methodology?

In addition, the following references additions are suggested regarding the research proposed by the authors:

·        https://doi.org/10.1007/s10518-021-01063-7

·        https://doi.org/10.1016/j.ijdrr.2021.102478

·        10.1016/j.engfailanal.2022.106207

·        arXiv:1509.09119[physics.geo-ph]

·        10.1016/B978-0-12-380938-4.00003-3

 

Comments for author File: Comments.pdf

Author Response

The authors would like to thank the reviewer for his/her constructive feedback. The manuscript has been revised according to the comments of the reviewer, which have provided valuable insights to improve it. In this document, the issues raised by the comments have been addressed in detail. The changes have been highlighted in red in the manuscript revised.

 

Response to reviewer n. 1

Q1: What is the meaning of "Identification of an analysis methodology […]" if the authors then use only 2 types of analysis? Please modify; Moreover, what are the reasons for choosing methods based on the vulnerability index over others?

The title has been revised according to the comment of the reviewer.

Among the existing method used for vulnerability assessment, the simplest approaches are known as empirical methods: in this study, they have been used for a quick and easy analysis of seismic risk at an urban scale by defining, for each masonry construction, a vulnerability index (VI) and a damage probability matrices (DPMs) method. Empirical methods are powerful tools for providing a preliminary screening of constructions’ fragilities on the territory, determining a sort of priority list for the execution of deeper investigations and for the following planning of retrofit interventions. Their limit otherwise lies in the constructions scenario to which they can be applied: their reliability progressively decreases when applied to structures considerably different with respect to the ones used for the method’s calibration. In addition, the lack of information coming from a survey may overlook critical epistemic uncertainties, influencing the results. Since these methods are applied through external onsite inspections, the level of confidence concerning the geometric composition, the material properties, the boundary conditions and loads involved among the orthogonal walls of the construction analysed depends on the available data and the experience of the technician.

 

Q2: It would be interesting to understand how the calibrations were performed concerning paragraph 2.2. The authors are requested to give more elucidations regarding the data used for the calibrations;

Thanks for the observation. As a matter of fact, what is meant for “calibration” concerned the collection of all the data available and elaboration of them according to what was needed for the application of the risk and resilience analysis. For instance, the data regarding the structure type of the buildings, when not available from archives, were deduced from the period of construction of the building. That means that “calibration of the essential data” seems not to be the correct definition of the process applied.

A more appropriated designation is provided in the revised manuscript.

 

Q3: In equation 1, did the authors take into account the regional modifier? Specify how;

In equation 1 it is not considered the regional modifier: as a matter of fact, Regional Vulnerability Factor allows to modify the VI * typological vulnerability index based on an expert judgment or on the basis of the historical data available. The first case is achieved when precise technological, structural, constructive information exists attesting an effective better or worse average behaviour. The second one occurs when data about observed damages exist. In both cases, this information is not available or not sufficiently reliable, so the authors preferred not to use it. It could be an interesting development of the research for the future.

Section 4 of the manuscript was changed as follows:

“The methodology experimented by Vicente would seem more suitable for describing the behaviour of Pombalino buildings, while that experimented by Polese appears to be more severe in predicting damage, but being the latter more rapidly applied and considering fewer parameters, it presents a greater degree of uncertainty even if with the same level of knowledge. This method could be improved by using the regional modifier in Equation 1as it has not been applied in this study because of the uncertanties related to the present dataset”

 

Q4: The authors in Tables 4, 5 and 6 show the results regarding the loss estimation. If so, are these matrices based on predictive analytics? What is the theory behind the quantification of losses? More clarifications are required;

The methodology adopts a shared approach in the Italian scientific community operating in the seismic vulnerability and risk field; it is based on the consensus on procedures to compute the risk in terms of expected damage for the residential building stock and associated consequences (direct economic losses and impact quantities such as unusable buildings, homeless and casualties), although allowing for the maximum freedom in the definition of the vulnerability/exposure model. The shared methodology was implemented by adopting the IRMA platform to evaluate national seismic risk and maps for the last National Risk Assessment (NRA). Default percentages adopted in IRMA Platform for the estimation of losses were used in the paper.

The corresponding references to this topic are the following:

Dolce, M.; Prota, A.; Borzi, B.; da Porto, F.; Lagomarsino, S.; Magenes, G.; Moroni, C.; Penna, A.; Polese, M.; Speranza, E.; et al. Seismic Risk Assessment of Residential Buildings in Italy. Bull Earthquake Eng 2021, 19, 2999–3032, doi:10.1007/s10518-020-01009-5.

Borzi, B.; Onida, M.; Faravelli, M.; Polli, D.; Pagano, M.; Quaroni, D.; Cantoni, A.; Speranza, E.; Moroni, C. IRMA Platform for the Calculation of Damages and Risks of Italian Residential Buildings. Bull Earthquake Eng 2021, 19, 3033–3055, doi:10.1007/s10518-020-00924-x.

For the sake of clarity, the missing references were added to the bibliography and the quantification of losses is better described in section 2.5 as follows:

“The risk maps combine the results of the damage maps to transform them into indicators of impact and losses according to specific formulations defined in [34]. The methodology adopts a shared approach in the Italian scientific community operating in the seismic vulnerability and risk field based on the consensus on procedures to evaluate the risk in terms of expected damage for the residential building stock and associated consequences. In particular, the impact gives the number of buildings that are usable, and unusable in the short and long-time span and those that have collapsed. Losses are expressed in terms of casualties, injuries, and economic losses.

Damage-risk matrices provide the rules for transforming damage levels into risk indicators. Each matrix provides for each level of damage the percentage to which it contributes an impact/loss: default percentages adopted in IRMA Platform [35] for the estimation of losses were used in the paper.”

 

 

 

 

Q5: The values proposed for the calculation of equation 5 should be validated based on European data. What do the authors suggest in this regard?

The values proposed in equation 5 have already been used in the 2011 Iorca earthquake (Spain) (Romão, X.; Paupério, E. An Indicator for Post-Disaster Economic Loss Valuation of Impacts on Cultural Heritage. International Journal of Architectural Heritage 2021, 15, 678–697, doi:10.1080/15583058.2019.1643948).

They also have been applied on two case studies in central Italy earthquake of 2016, for the city of Camerino and Vezzano in the PhD Thesis of one of the authors. These applications are not published yet but the thesis has already been revised. (Barchetta, L. Individuazione di una metodologia di analisi dei borghi storici situati nelle Marche meridionali per definire strategie d’intervento orientate all’implementazione delle capacità di resilienza. PhD Thesis, Università di Camerino, Ascoli Piceno, under review)

The manuscript is provided with additional comment according to reviewer’s suggestion in section 2.6 as follows:

“The values proposed in equation 5 have already been used in the 2011 Iorca earthquake (Spain) [21] and in two case in two case studies in central Italy earthquake of 2016, for the city of Camerino and Vezzano [27]”

 

Q6: What is the innovative aspect of the proposed research and what contribution does it make? What are the limitations of the applied methodology?

This paper explores the theoretical and methodological aspects of resilience assessment in historic centres. It adopts a simplified heritage-oriented approach, thus evaluating hazards and vulnerabilities with attention to the exposed multi-layered values (e.g. historic, architectural and artistic). The simplified methodology herein proposed can be applied to any type of cultural asset threatened by earthquake. Its general format can be used as a screening procedure for the preliminary risk analysis, to establish risk mitigation priorities or to identify assets requiring more detailed and resource-demanding analyses. The proposed methodology applies multidisciplinary analytical tools, combining heritage studies, civil engineering and risk analysis. The key elements for the success of this approach are that it is relatively simple to apply and all issues can be assessed as long as a good knowledge of the site is achieved. Novel elements derive from the evaluation of resilience for historic areas focusing also on tangible and intangible aspects for cultural heritage. The methodology has been validated on a case study, the historic center of Lisbon. The results represent the starting point for the proposal of intervention measures.

The limitation of the applied methodology lies in the constructions’ scenario to which they can be applied: the considerable number of data brings a great measure of uncertainties due to a lack of local ground motion recording or due to intrinsic uncertainties. The sources of this kind of uncertainties are many, such as errors in the building form compilation during the investigations, incorrect classification of the observed damage due to rapid execution of survey, and errors due to the poor experience of the technicians to identify the damage or that badly define the damage scales. Other uncertainties could come from differences in geometric/material properties and seismic design of structures of a given class, or to structural irregularities of a given class. On the intensity measure side, the uncertainties can be derived from a variation of the estimated level of intensity measure or from a lack of observed ground motion intensity levels. Moreover, the quantification of resilience is not quantitative, that may lead to a not objective assessment, however this kind of approach make it possible to take into consideration also intangible values that are fundamental in cultural heritage.

The manuscript was modified according to the reviewer suggestion in Section 4, as follows:

This paper explores the theoretical and methodological aspects of resilience as-sessment in historic centres.

“The methodology followed is effective on an urban scale, allowing easy identification of vulnerable buildings and the visualization of the geometries, favouring the interpretation of the spatial distribution of the phenomenon. Providing a geodatabase as complete as possible helps engineers and planners to obtain space-based seismic scenarios to assess the seismic damage of the building stock, report economic and human losses and plan quick responses. Novel elements derive from the evaluation of resilience for historic areas focusing also on tangible and intangible aspects for cultural heritage. The methodology has been validated on a case study, the historic center of Lisbon. The results represent the starting point for the proposal of intervention measures.

The two methods used for the assessment of seismic vulnerability are effective in giving a first interpretation of the expected damage, although, for a real result, it would be useful to deepen and calibrate the two methods. The methodology experimented by Vicente [14] would seem more suitable for describing the behaviour of Pombalino buildings, while that experimented by Polese [35] appears to be more severe in predicting damage, but being the latter more rapidly applied and considering fewer parameters, it presents a greater degree of uncertainty even if with the same level of knowledge. This method could be improved by using the regional modifier in Equation 1 as it has not been applied in this study because of the uncertainties related to the present dataset.

The limitation of the applied methodology lies in the constructions’ scenario to which they can be applied: the considerable number of data brings a great measure of uncertainties due to a lack of information, errors, incorrect classification etc”

Reviewer 2 Report

Manuscript ID: buildings-2102594

Title: Identification of an analysis methodology for historic cities to define strategies aimed at implementing resilience skills: the case of Lisbon downtown.

This paper is tailored to propose an operational framework for the resilience assessment applied to historic cities at the urban scale. This is achieved by multicriteria analysis based on the in-depth knowledge of the historical development of the city, past earthquakes, etc. Specifically, Lisbon downtown is selected as a benchmark to demonstrate the efficiency of the proposed framework. It is suggested that this paper should undergo a minor revision because it is well-written. However, some minor issues can be addressed before it can be publishable:

l  Abstract and introduction are too long and tedious, it is suggested to significantly shorten them in a well-organized fashion. Moreover, the literatures are not state-of-the-art or state-of-the-practice, recent publications should be added to strengthen the up-to-date literature.

l  There are many grammatic and puncturing issues. For example, there is not full stop between ‘scale’ and ‘Then’ (Page 1 Line 15). It is surprising that this appears in the abstract section.

l  The font size and of texts, figures and tables should be consistent. For example, the text of main body is Palatino Linotype and the text type of figures is Times New Roman.

l  The innovative contribution of this article should be well elaborated. As far as I can read, the proposed work merely proposes imaginary operations without a manner of demonstration. The novelty seems to be incremental so that the authors should clarify their contributions compared to the past work.

l  It is suggested that a quantitative or probabilistic analysis should be conducted to quantify the resilience, or in a perspective of risk-informed way.

l  The layout of size information of Fig 4 is not clear. It is suggested that figures with high resolution should be supplied in Fig 8.

Generally, this paper is well-written with sufficient demonstration and illustrative explanations. Acceptance can be made after a minor revision.

Author Response

The authors would like to thank the reviewer for his/her constructive feedback. The manuscript has been revised according to the comments of the reviewer, which have provided valuable insights to improve it. In this document, the issues raised by the comments have been addressed in detail. The changes have been highlighted in red in the manuscript revised.

 

Response to Reviewer n. 2

Q1: Abstract and introduction are too long and tedious, it is suggested to significantly shorten them in a well-organized fashion. Moreover, the literatures are not state-of-the-art or state-of-the practice, recent publications should be added to strengthen the up-to-date literature.

Literature was strengthened with up-to-date publications.

Abstract and introduction were reviewed trying to shorten without losing essential information.

 

Q2: There are many grammatic and puncturing issues. For example, there is not full stop between ‘scale’ and ‘Then’ (Page 1 Line 15). It is surprising that this appears in the abstract section.

The entire paper punctuation and grammar has been reviewed.

 

Q3: The font size and of texts, figures and tables should be consistent. For example, the text of main body is Palatino Linotype and the text type of figures is Times New Roman.

The font size has been reviewed.

 

Q4: The innovative contribution of this article should be well elaborated. As far as I can read, the proposed work merely proposes imaginary operations without a manner of demonstration. The novelty seems to be incremental so that the authors should clarify their contributions compared to the past work.

This paper explores the theoretical and methodological aspects of resilience assessment in historic centres. It adopts a simplified heritage-oriented approach, thus evaluating hazards and vulnerabilities with attention to the exposed multi-layered values (e.g. historic, architectural and artistic). The simplified methodology herein proposed can be applied to any type of cultural asset threatened by earthquake. Its general format can be used as a screening procedure for the preliminary risk analysis, to establish risk mitigation priorities or to identify assets requiring more detailed and resource-demanding analyses. The proposed methodology applies multidisciplinary analytical tools, combining heritage studies, civil engineering and risk analysis. The key elements for the success of this approach are that it is relatively simple to apply, and all issues can be assessed as long as a good knowledge of the site is achieved. Novel elements derive from the evaluation of resilience for historic areas focusing also on tangible and intangible aspects for cultural heritage. The methodology has been validated on a case study, the historic center of Lisbon. The results represent the starting point for the proposal of intervention measures.

The limitation of the applied methodology lies in the constructions’ scenario to which they can be applied: the considerable number of data bring a great measure of uncertainties due to lack of local ground motion recording or due to intrinsic uncertainties. The sources of this kind of uncertainties are many, such as errors in the building form compilation during the investigations, incorrect classification of the observed damage due to rapid execution of survey, and errors due to the poor experience of the technicians to identify the damage or that badly define the damage scales. Other uncertainties could come from differences in geometric/material properties and seismic design of structures of a given class, or to structural irregularities of a given class. On the intensity measure side, the uncertainties can be derived from a variation of the estimated level of intensity measure or from a lack of observed ground motion intensity levels. Moreover, the quantification of resilience is not quantitative, that may lead to a not objective assessment, however this kind of approach make it possible to take into consideration also intangible values that are fundamental in cultural heritage.

 

Q5: It is suggested that a quantitative or probabilistic analysis should be conducted to quantify the resilience, or in a perspective of risk-informed way.

It is noted that damaged cultural heritage has also non-economic impacts on several domains of society, namely on social cohesion and community participation, education and knowledge, social identity, well-being and quality of life, environmental sustainability. Concerning cultural heritage some aspects are not quantifiable through quantitative analysis and it has been studied the most objective way to assess it. For instance, the loss of the social or spiritual value associated to the cultural heritage asset can have deep social impacts, namely in the sense of identity, continuity and belonging of people. Given the difficulty to relate these impacts with economic indicators, the risk map itself was not able to capture them.

 

l The layout of size information of Fig 4 is not clear. It is suggested that figures with high resolution should be supplied in Fig 8.

Resolution was implemented