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 90 Energia, ambiente e innovazione | 4/2016 QUADRO INTERNAZIONALE_ 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.

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