How to Evaluate and Mitigate Vulnerability of Historical Buildings

QUADRO INTERNAZIONALE_

How to evaluate and mitigate vulnerability of historical buildings. A Spanish project experience

RIVUPH and ART-RISK projects implemented new approaches based on multidisciplinary analysis of environmental hazards and vulnerability in order to develop global conservation strategies. Such strategies can both minimize the deterioration of monuments and reduce the cost of isolated interventions, contributing to the preservation of cultural heritage

DOI 10.12910/EAI2016-064 by Rocío Ortiz Calderón and Pilar Ortiz Calderón, University Pablo de Olavide, Dpt. Physical, Chemical and Natural Systems (Seville, Spain)

88 Energia, ambiente e innovazione | 4/2016 ow should we preserve is a wide-ranging field that includes Preventive conservation implies historical heritage against the analysis of threats at different knowing the risks that a monument floods, earthquakes or scales and scenarios, from a coun- is subject to and acting over the human actions? Images try to a statue. Most studies are causes of these risks (hazards and hof Louvre museum during the flood carried out on archival materials level of vulnerability). Considering in Paris in 2016 have shown the need or well-known artworks in muse- the great number of non-desired of being prepared to know which ums, due to the fact that insurance events that could cause damage to monuments could suffer these types costs have risen dramatically in the a monument, the difficulty resides of accidents and which monuments last decade. But what happens to in the possible need of classifying are more vulnerable. In fact, our cul- the monuments of our cities? This and prioritizing, as well as being tural heritage is continuously threat- is one of the questions that we are prepared to face a range of extreme ened by hazards of different kinds trying to answer with our research. situations. and intensity. Against those threats, Whole monuments or cities are The knowledge of risks and hazards we should know how to prioritize rarely studied under a risk method- are based on experience and the ar- our actions and face emergencies. ology and their analyses are usually chive of past and ancient episodes Studying hazards and vulnerability based on the assessment of main and disasters. Risk management tries of our cultural heritage is one of the risks. New approaches are currently to use this information to decide the ways that we have to evaluate, and being developed to analyze multi- best strategies for preventive con- possibly mitigate, those threats to scenario risks for monuments in servation. The current crisis leads to our historical heritage. a city [1], with a huge bulk of data prioritize strategies in a town, as the and scenarios that demand simpli- urban unit where territorial policies Introduction fied models for decision-makers. could be applied, and moreover in a region where the restoration budget Monuments and their artworks are Risk versus vulnerability: is distributed. For this reason our elements that belong to the history Two concepts linked aim is to analyse a list of monuments and tradition of a country. They in a city and give the order of inter- are also a high source of economi- Concepts regarding risk and vulner- vention [1, 3-4]. Rivuph (start-end) cal income and represent the level ability were defined, in 1993, by the and Art-Risk (start- end) are two of social-economic development European committee for the defense Spanish projects developed to face of a region. However, most of the of cultural heritage [2]. Vulnerability this challenge: historical infrastructures endure is the level of tenacity or weakness continuous deterioration. This is of a monument that faces outside RIVUPH (https://www.upo.es/ caused by the steadily increasing at- hazards, even if these threats have tym/en_rivuph.html) is a project mospheric contamination, manage- a different origin: natural disasters, of the Andalusian government ment problems and severe damage actions caused by meteorological (Spain) based on the analysis caused by natural accidents or the agents, and human actions. Risk de- of environmental risk in his- lack of respect by people. Therefore, pends on both factors, because an torical cities in order to develop the knowledge of vulnerability of ill monument is more vulnerable, conservation strategies that can our monuments against exceptional and increases the probability of in- minimize the deterioration of (floods, earthquakes, fires, vandal- fection with an illness (threat). In monuments. With this purpose, ism, wars, etc.) or continuous (con- summary, the degradation of monu- multi-scenario risk maps of sev- tamination, climate change, ther- ments could be due to the effects eral towns have been drawn with mohygrometric conditions, etc.) of: structural damages, weathering Geographic Information System threats allows the analysis of risk affection, pollution agents or other (GIS) software to provide infor- probability and intensity in order anthropogenic factors; whereas the mation about the probability of to take the needed awareness-rising conservation degree of each monu- the main hazards in a neighbor- measures for the conservation of ment is vulnerability, its evaluation hood. Hazards have been classi- historical heritage. is an indirect function of the level of fied in three categories: 1) Static- Reducing risk to cultural heritage deterioration. structural hazards, that include

4/2016 | Energia, ambiente e innovazione 89 seismic factors, landslides, floods, have the following questions: how to simulate their reasoning and coastal dynamics, avalanches, to carry out an accurate evaluation knowledge. As different experts volcanic activity, underground on different buildings in the same have different opinions, this is the water, geotechnical factors, etc. city? Have different technicians base of value of a DELPHI meth- 2) Environmental-air hazards the same opinions about the vul- odology. We combine this meth- as erosion (wind, rain, sea, or nerability? Is the citizens` opinion odology with a double entrance river), pollution (vehicle conges- different from experts’ consider- matrix that allows to evaluate the tion, traffic roads, industry, etc.), ations? Guess that you have the conservation degree, that is vul- weather (rain, temperatures, dew responsibility to maintain all the nerability. points, etc.); and vibrations. 3) building of a city and your bud- • Fuzzy logic. This method allows Anthropogenic factors (fires, ac- get is not enough (real situation to evaluate the range of opinions cessibility to the monument, stressed during this crisis), which of each expert. In contrast with

Town/City Carmona Estepa Osuna Marchena Seville Mitigation Action (Inhabitants) (28,679) (12,397) (17,800) (19,768) (702,355) All monuments must be under year- Monuments studied 19 17 20 11 30 ly surveillance and global maintenance plan Very low damage Preventive maintenance plan and 6 6 8 1 (<10%) periodic inspections Preventive maintenance plan and Low (10-25%) 11 9 10 9 13 periodic inspections with minor interventions Vulnerability Further studies and likely interven- Evaluation Moderate (25-50%) 1 2 2 2 15 tion in a long period 1 1 (Sa- Intervention is recommended in a High (50-75%) (Alcazar) grario) short period of time (6-12 month) Catastrophic/ Very Urgent Intervention (<3 month) High damage (>75%)

Methodology applied [1] [1] [1] [1] [3] Tab. 1 Evaluation of monument vulnerability and mitigation action proposal

tourist pressure, population, etc.). must be the first buildings to be Boolean logic that only has two On the other hand, factors with restored or reinforced? Under this values (well or bad, yes or not), potentially positive effects on re- frame of questions, we proposed our diagnosis language has plenty duction of monument deteriora- two different approaches based on of possibilities between a well- tion have also to be considered; artificial intelligence tools: and a bad-conserved monument, these elements can include town- for instance the roof is well con- planning protection. • DELPHI Methodology. This served but we have problems of ART-RISK (https://www.upo.es/ method is based on the predic- capillarity. Fuzzy logic allows us investiga/art-risk) is a project of tion of experts, its name comes to evaluate these differences and, the Spanish government based on from the Greek sanctuary of Del- as an artificial intelligence tool, the analysis of vulnerability, as the phi, an oracle that was consulted try to imitate the rationalization degree of a monument weakness. on important decisions. Similarly, of experts. This evaluation needs the opinion we consult a multidisciplinary of experts. But, after years of diag- group of 7-8 experts about their Weighted factors were obtained con- nosis for cultural heritage, you may opinion of vulnerability and try sulting the multidisciplinary group

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Evaluation of vulnerability in Monuments of Andalusia (Spain)

Vulnerability has been evaluated in more than two hundred monuments in Andalusia (South Spain). This diagnosis has allowed to develop a cog- nitive diagram of the relationships between different variables and the vulnerability index to improve the method of risk analysis. Conditions of foundation, structure and con- structive systems have the highest weight when evaluating vulnerability according to experts´ opinion, as these variables could produce a par- tial or total loss of monuments and their artworks, especially in seismic zones. Physical-chemical charac- teristics, texture and fire-resistance Fig. 1 Seismic hazard map of Andalusia (Spain) define the conservation degree of materials and have a medium influence, which is mainly dominated of experts to evaluate the influence ity of several monuments of histori- by nature and quality of materials. of each hazard and to overlap the cal cities. Aesthetic appearance has the low- factors in the risk map, and to evalu- These assessments of threats imply est influence in the opinion of ex- ate the illness of the buildings. Under collecting, georeferencing, weight- perts and citizens. Other variables as this objective, it is clear that risk anal- ing according to Delphi results and simplified building, urban planning ysis following from the evaluation of overlapping data from local, re- protections and level of usage have cultural heritage needs experts from gional and national institutions of to be also assessed, according to the different countries and specialties, as weathering, risk, environment, ur- type of construction, local and/or re- well as opinions of citizens that en- banism, territorial governance, so- gional law and data of tourism office joy, use the monuments, or simple ciology statistics, tourism, geology, and owners [3]. live near them. Consequently, we are hydrogeology, etc.. On the other As an example, Table 1 summarizes using the social network to validate hand, vulnerability needs an on- the evaluation carried out in well- the opinions of experts and to im- site study, where the frequency and known monuments of Marchena, prove the methodology (http://www. weathering degree were taken into Osuna, Estepa, Carmona and Se- upo.es/tym/rivuph/en_encuestas. account. Although it is not possible ville. These five cities have historical php or http://www.ecomimesis.com/ to have every hazard in the same centers, and the monuments chosen analisis-vulnerabilidad-patrimonio- city, this general approach allows us belong to the Roman, Muslim or historico). Expert consultations and to know the main risk and compare Christian periods. social network analysis have allowed the results obtained in different cit- 75% of the monuments assessed ex- to develope a new validated criteria ies for regional decision-makers. hibited a very low or low degree of based on the Delphi method, that Meanwhile, each hazard has a fre- vulnerability, which means a vulner- forecasts the evolution of a provided quency and intensity that varies ac- ability evaluation of less than 25%, situation asking their opinion to a cording to the environmental con- so they would need a preventive limited number of experts [1]. This ditions in the different districts of maintenance plan and periodic in- methodology has been used to con- the city. This data is useful for local spections with minor interventions. sider the hazards and/or vulnerabil- decision-makers. Two monuments (Alcazar in Car-

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mona and Church of Sagrario in Se- gies must be updated in the case of and 2c show, respectively, a zoom ville) have the highest vulnerability changes or interventions, and it is of the georeferenced map of static- evaluation, due to important struc- advisable to repeat the analysis at structural hazards and the hazard tural problems, which means they least every three years or after di- map for road-traffic in the area of must be the first to be restored or sasters such as floods, fires, earth- Sagrario and Cathedral of Seville. reinforced against structural threats. quakes, etc. Figure 2b shows, in orange and yel- Intervention is recommended in a At the local scale, the multiscenario low, that the block of Sagrario/Ca- short period of time (6-12 month). analysis of the cities showed that thedral has a medium-high risk of First floor and basement of Sagrario the maps of risk in Estepa and Car- floods and damage due to capillar- are now under restoration study due mona were dominated by landslide ity humidity [5]. Meanwhile other to their collapse. hazards, due to the presence of clay monuments, such as Church of Twenty-two of the monuments pres- minerals around the edge of the Santa Ana (STA), have a high vul- ent moderate vulnerability, which hills. In Carmona, this risky area is nerability due to the effect of capil- according to the uncertainty associ- just where the Alcazar is located, the larity and they must have an evacu- ated with this methodology implies further studies. In general, the vulnerability evaluation stressed that these cases were mainly affected by impacts associ- ated to continuous erosion (humidity, change of temperature and wind pressure), anthropogenic interventions, vandalism and pollutants. About pollution, it is worth empha- sizing that the most common stones in these five cities are calcareous sandstones, calcarenites and lime- stones that are especially vulnerable to road-traffic pollutants. The overlap between vulnerability and the main threats provides further information at the regional or local level. As an example, Figure Fig. 2 Map of vulnerability of the monuments studied in Seville (a); a zoom of the georeferenced 1 shows the risk map due to earth- map of static-structural hazards (b); the hazard map for road-traffic in the area of Sagrario and Cathedral of Seville (c) quake in Andalusia: the cities studied have low risk of earthquake, but repetition of episodes as the earth- risk of landslides added to its high ation protocol in the case of floods. quake of Carmona (1504) and Lis- vulnerability index, and earthquake The north façade of the block Ca- bon (1755) could have important possibilities worsened the situation thedral/Sagrario has the highest risk consequences for the buildings with and demonstrated the necessity of due to vehicle traffic (street colored medium or high vulnerability, so it interventions and special conserva- in orange, Fig. 2c) that may pro- is important to reinforce structures tion with inspections and checking duce black crust and deposits. Even at least in the Church of Sagrario. In in the Alcazar. though experts consider pollution fact, some weathering forms detect- The study of hazard maps, over- as a minor threat, its continuous ef- ed during vulnerability evaluation lapped with vulnerability of Seville, fects generate façade damage and in Monuments of Seville, Carmona has been chosen as an example of huge cleaning budgets, so traffic is and Estepa highlighted stability in- local study (Fig. 2). Figure 2a shows an environmental hazard that has to fluence. In any case, vulnerability the map of vulnerability of the mon- be taken into account in most of the evaluation and mitigation strate- uments studied in Seville. Figures 2b cities. This hazard is enhanced by the

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calcareous stones employed in both Conclusions lyze strategies for cultural heritage buildings. conservation in a region, or inside To mitigate this effect, the five cit- In summary, the vulnerability evalu- a city, and evaluate the hazards of ies require an urban plan for vehicle ation methodology is an artificial different zones in order to establish traffic control to avoid driving near intelligence tool that reproduces mitigation plans. the main monuments, in order to the opinion of experts to evaluate decrease the weathering due to traf- the conservation degree of a monu- Acknowledgments fic pollution. ment and allows to prioritize future Another factor to analyze is the interventions to mitigate the dam- This paper has been supported and adoption of urban protection mea- age. This methodology, based on based on the Methodology devel- sures. As an example the detailed the overlapping of hazards and vul- oped by two Projects: RIVUPH, evaluation of urban planning in the nerability elements, is very useful to an Excellence Project of Junta de city of Marchena [6], theoretically identify, evaluate and prioritize the Andalucia (code HUM-6775), and a positive factor, evidences the loss restoration interventions in a city Art-Risk, a RETOS project of Min- of buildings that should have been and to address preventive conserva- isterio de Economía y Competi- protected. The public administra- tion also in the region by using a sci- tividad and Fondo Europeo de De- tions were informed of this irregular entific approach. sarrollo Regional (FEDER), (code: situation in 2012, but unfortunately This procedure provides protocols BIA2015-64878-R (MINECO/ we do not have evidence that any ac- to develop policies for decision- FEDER, UE)). tion has been taken since then. So it making when preservation of is necessary to improve the instru- historical centers is needed. This For further information, please ments of control and the inspections methodology allows to compare contact: over the local authorities. risks between different cities to ana- [email protected]

REFERENCES

1. P. Ortiz, V. Antunez, J.M. Martín, R. Ortiz, M.A. Vázquez, E. Galán (2014). “Approach to environmental risk analysis for the main monuments in a historical city”, Journal of Cultural Heritage, Vol. n. 15, 432-440 pp. 2. Consejo de Europa (1993). “Recomendación (93)9. Recomendación relativa a la protección del Patrimonio Arquitectónico contra las catástrofes naturales” 3. R. Ortiz, P. Ortiz (2016). “Vulnerability Index: a New Approach for Preventive Conservation of Monuments”, International Journal of Architectural Heritage, published online, 1–23 pp. http://dx.doi.org/10.1080/15583058.2016.1186758 4. A.J. Prieto, J.M. Macías-Bernal, M.J. Chávez, F.J. Alejandre (2016). “Expert system for predicting buildings service life under ISO 31000 standard. Application in architectural heritage”, Journal of Cultural Heritage, Vol. n. 18, 209-218 pp. 5. R. Ortiz, P. Ortiz, J.M. Martín, M.A. Vázquez (2016). “ A new approach to the assessment of flooding and dampness hazards in cultural heritage, applied to the historic centre of Seville (Spain)”, Science of the Total Environment, Vol. n. 551-552, 546-55 pp. 6. R. Ortiz (2012). “La (des)protección del patrimonio histórico de Marchena”. MSc Thesis, Universidad de Sevilla

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