Pathologic and Risk Analysis of the Lojuela Castle (Granada-Spain): Methodology and Preventive Conservation for Medieval Earthen Fortifications
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applied sciences Article Pathologic and Risk Analysis of the Lojuela Castle (Granada-Spain): Methodology and Preventive Conservation for Medieval Earthen Fortifications M. L. Gutiérrez-Carrillo 1,* , I. Bestué Cardiel 2, E. Molero Melgarejo 3 and M. Marcos Cobaleda 4 1 Departamento de Construcciones Arquitectónicas, Universidad de Granada, 18071 Granada, Spain 2 Departamento de Expresión Gráfica Arquitectónica y en la Ingeniería, Universidad de Granada, 18071 Granada, Spain; [email protected] 3 Departamento de Urbanística y Ordenación del Territorio, Universidad de Granada, 18071 Granada, Spain; [email protected] 4 Departamento de Historia del Arte, Universidad de Málaga, 29071 Málaga, Spain; [email protected] * Correspondence: [email protected]; Tel.: +34-958241000 (ext. 20034) Received: 2 July 2020; Accepted: 12 September 2020; Published: 17 September 2020 Abstract: This study presents a methodology generated for the preventive conservation of defensive earthen architecture, applied to the case of the Lojuela Castle (Lecrin Valley, Granada, Spain). In the application of the designed protocol, a multidisciplinary analysis of its patrimonial characteristics and multidimensional evaluation was developed, applying the technique of qualitative consultation to a group of experts—the Delphi method. This methodology allowed us to relate the hazard factors and the vulnerability of the asset for each group of risks that affect it. The support of the method in with geographic information systems (GIS) has favored the production of predictive cartography and risk analysis—including the territorial dimensions and spatial interactions of the asset with the physical environment. This has facilitated the obtention of micro-zoning maps of each of the risks examined. The risk mapping in micro-zoning and the knowledge of the structure’s vulnerability represents an important contribution to the future conservation and management of this heritage. They favor strategies that minimize the incidence of risks and allow the prioritization of the conservation actions with a minimum economic investment, creating an efficient maintenance program. This will facilitate the protection, conservation and valorization decisions by the administration and the competent bodies involved in the protection of these sites. Keywords: risk factors; preventive conservation; medieval earthen defensive architecture; pathologic analysis 1. Introduction During recent years, the model of action on cultural heritage has tended to protect, preserve and safeguard this heritage, promoting its enrichment and use as a social asset and a factor of sustainable development. In this way, the model contributes to reducing the challenge represented by the transformation processes that suffer and which compromise its meaning, values, integrity and diversity [1]. A large part of the cultural legacy suffers a significant process of degradation due to the constant action of different factors of alteration, both natural and anthropic [2]. It is worth highlighting the high exposure of these to the action of environmental factors [3], in addition to those related to geomorphological actions [4–6] or the action of floods and fires [7]. The factors of anthropic origin must also be added: acts of vandalism, inappropriate restorations or the absence of urban planning that is in Appl. Sci. 2020, 10, 6491; doi:10.3390/app10186491 www.mdpi.com/journal/applsci Appl. Sci. 2020, 10, 6491 2 of 33 line with the protection of heritage. Among the causes that increase the effects of the previous ones, it is necessary to emphasize the lack of adequate maintenance of these structures [8,9], which is responsible for material damage of the asset as well as the loss of heritage values, even compromising the safety of people. The damage caused not only affects each specific asset, but also encourages the degradation of the environment. Considering this reality, the design of preventive conservation and maintenance strategies is essential in order to guarantee more sustainable protection and conservation [10–12]. Attention to the threats and the situation of degradation of heritage as a tool to prevent major deterioration and extend the life of buildings [7,13] has had a decisive influence on updating and rethinking the protocols for analysis and intervention in cultural heritage. This practice has resulted in a significant reduction in the economic investments necessary for its restoration and repair of damage. The elaboration in 1987 of the Charter of the Risk of Cultural Heritage in Italy marks a real turning point. This Charter was based on the determination of systems and procedures that made the schedule of maintenance and conservation interventions possible and had a direct application in theoretical and methodological developments and operational plans for programmed conservation [14]. From the perspective of a territorial vision, the main factors that cause the deterioration of cultural assets were analyzed and maps and risk charts were generated as an essential planning tool in the practice of preventive management of cultural assets. Nevertheless, this planning tool worked from the macrozoning perspective, not from the detail of the microzoning, which represented a key factor in the correct diagnosis. It should be noted that the Charter did not address the notion of vulnerability [15]. From that moment, the use of the spatial analysis capabilities of geographical information systems (GIS) as a tool for evaluation, diagnosis and control in the field of conservation [16] and from the perspective of territorial planning and risks has been increasing. Some studies have highlighted the absence of hazard maps in urban plans, calling for their inclusion [12]. Other works provide information on the probability of hazards in urban areas to prioritize preventive conservation actions and restorations [17] or others identify areas susceptible to geomorphological hazards that threaten cultural and natural heritage [6]. Moreover, the studies that focus on the development of analytical methodologies for risk assessment and treatment control are outstanding. They combine GIS and digital image analysis (DIA), used in assessing the effectiveness of biocides [18], the study of black crusts on buildings [19] or the effect of traffic on the facades of stone buildings [20]. In recent years there has been an increase in studies on the conservation of cultural heritage. The origins of preventive conservation and its historical evolution have been highlighted [21,22]. However, the advance of this model of action from other disciplines has played a fundamental role in the development of applied science with a specific technology [23–26]. This fact has made possible a greater and better knowledge of the cultural asset and its materiality, as the origin of intrinsic risks [27] or of the evaluation of threats [28]. Satellite remote sensing systems have been integrated into the study for risk assessment [29], even in combination with dispersive X-ray spectroscopy (SEM-EDX) to determine small-scale pathologies in walls [30]. Other research has focused on the development of methodologies based on the use of artificial intelligence, creating models for predicting the useful life of the building based on fuzzy logic, which determines and evaluates the factors that affect vulnerability and risks that affect the asset [15,31]. There are other models based on prediction methodologies supported by statistical probability data [32]. The works that employ multicriteria techniques such as analytical hierarchy process (AHP) must be added. The application of the AHP has allowed the assessment of the appropriateness of a change of use, different from the original, in industrial buildings, without reducing their heritage values. This change contributes to their sustainable conservation [33] and has allowed a new approach for developing evaluation models of the potential sustainable energy rehabilitation of historical buildings [34]. It should be pointed out that the identification, evaluation and control of certain variables from multidisciplinary approaches for the design of preventive conservation and maintenance strategies were mainly developed in the context of museums [26,35,36]. However, the Vantaa Resolution [37] and the Krakow Charter [11] have extended the scope of preventive conservation and extend the Appl. Sci. 2020, 10, 6491 3 of 33 intervention model to any cultural asset, including buildings. Since then, preventive conservation has become the main strategy of European policies in the field of heritage conservation [38,39]. Actions within the framework of preventive conservation [40] imply the definition of an effective and systematic methodology to identify [38], evaluate and control the threats that affect all cultural assets [41–46]. The aim of these actions is to minimize these threats [47–50], thanks to the evaluation of their degree of impact on the effects of deterioration and the development of appropriate measures to avoid or, at least, slow down their negative effects [39,51]. The strategy established should focus on the multidisciplinary analysis of the cultural asset, its state of conservation and the use and management thereof; the examination of the risks of deterioration, assessment and definition of priorities for action; the establishment of monitoring and control methods, as well as the definition of technical means and working procedures, together with maintenance planning and the design of preventive interventions [52]. At this point, the