1,721,053 research outputs found
La gestione del rilievo del danno: modelli IFC per il patrimonio storico / Damage survey management: IFC models for historical heritage
No full textL’articolo elabora un approccio OpenHBIM per la digitalizzazione del quadro di danno degli edifici esistenti, basato sulle Industry Foundation Classes. Viene sviluppato un database che integra i dati raccolti, implementati secondo classi e proprietà standardizzate, e la definizione di relazioni tra le entità, promuovendo la gestione condivisa delle informazioni. L’interoperabilità dello strumento facilita infine l’avvio di successive fasi analitiche, quali la modellazione strutturale dello stato di fatto.
The paper elaborates an OpenHBIM approach for the digitalisation of the crack pattern in existing buildings, based on Industry Foundation Classes A database is developed, which integrates the collected data, implemented according to standardised classes and properties, and the definition of relationships between entities, enhancing the shared management of information. The interoperability of the tool enables the development of subsequent analytical steps, such as structural modelling of the current state
Correlation of vulnerability and damage between artistic assets and structural elements: The DataBAES archive for the conservation planning of CH masonry buildings in seismic areas
Full text linkHistorical buildings in seismic hazard-prone regions need specific measures in safety protection, largely due to the presence of artistic assets and/or decorations, both movable (e.g., statues, pinnacles, etc.) and unmovable (e.g., frescoes, valuable plasters or wall paintings, mosaics, and stuccoes). A correlation of damage between structural systems and artworks is fundamental for defining limit states, which can identify the proper conditions for interventions. Nevertheless, several vulnerability aspects can be identified before a seismic event occurs, the study of which can provide the basic dataset for setting up preventive measures in conservation programs. In this paper, the vulnerability and damage conditions related to structural elements (SE) and unmovable artistic assets (AA) belonging to historical masonry buildings are analysed. Optimized survey forms for the onsite detection of either intrinsic (e.g., compositional) defects or deterioration phenomena for both materials and structure are proposed, and results are provided in a web data system (called DataBAES). This enables us to compare the current levels of vulnerability and damage of AA and SE on a scale of five increasing grades. This procedure has been validated on a series of buildings struck by earthquakes in Italy and can be used for correlations of the seismic behaviour of SE and AA in predictive analyses
Assigning the macroseismic vulnerability classes to strengthened ordinary masonry buildings: An update from extensive data of the 2016 Central Italy earthquake
No full textDamage scenarios caused by the 2016 Central Italy earthquake confirmed the relevant role of interventions on masonry buildings’ seismic performance, also by increasing (rather than reducing) their vulnerability. Notwithstanding, current literature procedures aimed at assigning to buildings an European Macroseismic Scale 1998 (EMS-98) vulnerability class (A to F) do not consider such influence especially referring to the several intervention techniques applied to masonry buildings since the 1980s in Italy. This impaired a proper matching of vulnerability classes to the real performances, as strengthened buildings are conventionally assigned to average vulnerability conditions (class C). In the present work, vulnerability classes are appropriately assigned to buildings in strengthened conditions, basing on the analysis of 2264 dwellings placed in 19 settlements. Inspections were carried out with a purposely developed rapid visual screening procedure. A performance-based definition of structural types considered a building's masonry quality, diaphragms' stiffness, and kind of interventions graded between downgrading and upgrading. Types with the same behaviour were grouped into vulnerability classes, in the full range from A to D, through a literature model compatible with the EMS-98. Rubble stone buildings with downgrading or worsening interventions behaved like those in original conditions (class A), whereas improved buildings typically performed like class C. Upgrading interventions led to class D, similarly to modern clay block buildings. Masonry quality influenced the classification more than diaphragms' stiffness. The empirical membership of each type to vulnerability classes was obtained, that which allowed to include variously strengthened masonry buildings within the EMS-98 framework
Protection of cultural heritage buildings and artistic assets from seismic hazard: A hierarchical approach
Full text linkThe occurrence of natural disasters such as earthquakes represent a worldwide challenge in the conservation of cultural heritage (CH), which suffer from damage due to high vulnerability conditions. Therefore, the protection of CH from seismic hazard is of paramount importance. Damage and vulnerability assessment of CH and artistic assets play a key role in the identification of conservation strategies. Effective strategies require the stabilization of severely damaged buildings and the preventive improvement of constructions structural response to seismic actions. Although the operation of emergency inspections is meant to classify buildings on the basis of buildings residual seismic capacity, investment decisions in restoration and conservation strategies of such vulnerable structures must take into consideration tangible and intangible values of both building structures and artistic goods as well as must combine objectives of verifying structural safety standards and preserving cultural heritage significance. Damage and vulnerability assessment depend on different criteria, which, on the one hand, are related to buildings structural characteristics, materials, and geometrical properties. On the other hand, to the peculiarities and uniqueness of artworks and artistic goods present on structural elements. In this paper, an AHP (absolute) model is proposed to rank multi-criteria prioritization of protection and restoration interventions on a set of 15 churches, which were damaged by earthquakes, occurring in Italy in the last decades. In detail, in order to structure the decision problem, identify key factors, and define the hierarchy, we conducted an extensive literature review and interviewed a pool of experts. Focus groups were organized to develop the set of criteria and sub-criteria and validate the hierarchy by dynamic discussion
Seismic assessment and numerical modelling of the Sarno Baths, Pompeii
No full textSeismic assessment of archaeological sites has an increasing role in the definition of reliable conservation strategies of such vulnerable structures, with the combined objectives of verifying the structural safety to code standards and preserving the cultural heritage significance. Aging of materials, anthropogenic and environmental factors may cause in fact rapid loss of the structural capacity once ruins and ‘remaining structures’ are discovered and excavated. This paper reports the seismic vulnerability assessment of the Sarno Baths in Pompeii. After a detailed diagnostic phase (through non-destructive on-site tests) to increase the knowledge of masonry structures regarding the quality of materials, connections and dynamic behavior, various methods of structural analyses are applied and compared. Both analytical and numerical approaches are tested to understand the structural behavior against design actions, identify the original causes of the detected damage pattern, identify the resisting mechanisms, and predict the response for exceptional events (i.e. earthquakes). Outcomes of ambient vibration tests are used to calibrate the properties of the constitutive materials (mass density, elastic modulus), to clarify the interaction with surrounding domains (the building is placed on a slope), and to highlight any damage conditions in the building (diffuse cracking, decay of materials, etc.) influencing its seismic performance
Seismic response of masonry buildings in historical centres struck by the 2016 Central Italy earthquake. Calibration of a vulnerability model for strengthened conditions
Full text linkBrought to light by the 1997 Umbria-Marche (Italy) earthquake for the first time, the theme of damage patterns of masonry buildings with structural interventions became urgent again in the 2016–17 Central Italy seismic swarm. On a sample of 2306 buildings within the seismic field, the 85% bears the signs of structural interventions. With the aim of inferring the vulnerability factors from damage of strengthened buildings, a close-up analysis revealed that interventions can cause damage to the structures on which they are applied because of i) poor detailing and ii) incompatibility among parts, old and new. These conditions limited the attainment of a building's box-like behaviour and, therefore, an unfavourable contribution of interventions was identified. Conversely, a favourable contribution was determined. The analytic comparison between the behaviour of building types with interventions and that of the vulnerability classes of the European Macroseismic Scale (EMS-98) obtained a vulnerability model for empirical data. Buildings whose interventions had an unfavourable contribution are comparable with ‘original’, unreinforced ones; conversely, a favourable contribution permitted them to approach the behaviour of modern masonry structures. This work represents a first step towards the inclusion of strengthened buildings in the EMS-98 vulnerability system
Intervention strategies for the seismic improvement of masonry buildings based on FME validation: The case of a terraced building struck by the 2016 central italy earthquake
Full text linkResidential masonry buildings represent a large stock among highly vulnerable structures in medium–high seismic hazard areas, often built without any anti-seismic provisions. Their rehabilitation and/or strengthening according to optimised intervention strategies is topical and may contribute to revaluating zones characterized by depopulation phenomena. In this paper, a terraced building struck by the 2016 Central Italy earthquake is analysed through a frame by macro element (FME) model. The building is composed of six two-storey units made of stone and clay block masonry walls and semi-rigid diaphragms. The numerical model was calibrated based on the damage pattern caused by the earthquake and then used to carry out parametric analyses on the strengthened conditions by simulating both one unit and the entire terrace. The effects of interventions applied to either vertical or horizontal components, both singularly and in combination, were analysed in terms of nonlinear static analyses, and quantified by a performance factor, according to the upgraded seismic code in Italy. Kinematic analyses also completed the assessment of the building. Results compared the capacity of interventions in attaining the targets defined for improvement at both local and overall levels
Conservation of historical constructions in seismic area: experimental research on enhancement techniques for masonry buildings
No full textConservation of CH buildings requires, in the past as today, a deep knowledge of the behaviour of structures and components under deterioration and damage conditions, as well as a suitable experience of the effects of intervention solutions, aimed at enhancing the mechanical performance of the built assets. Seismic hazard constitutes one of the most severe causes of damage and failures for existing structures, particularly for masonry buildings, as they are affected by typical vulnerabilities, due to their constructive systems, degradation of materials, and other specific weaknesses accumulated in the course of time.
A proper selection of materials and techniques is required to face and mitigate those critical conditions, and their validation by experimental research is fundamental, in order to quantify the potential improvement, but also to clarify the contexts of possible restrictions in their use.
The paper presents and discusses a series of intervention techniques adopted in historical masonry building for seismic improvement. Some significant results of experimental research carried out at the University of Padova, aimed at characterizing the performances of modern and innovative materials applied to traditional and more recent or new techniques are also described
Ottimizzazione di elaborazioni termografiche per il monitoraggio dell’umidità di risalita in edifici murari risanati con tecnologia a neutralizzazione di carica
No full textRising damp in masonry buildings is a challenging issue and a continuous threat to the conservation of historical heritage. Moisture in the walls can provoke irreversible damage to artistic assets, due to the triggering of chemical, physical and mechanical deterioration phenomena (e.g., spalling, migration of salts). New technologies based on electric charge neutralization (CNT®) permit non-intrusive and effective actions to counteract the rising damp and stabilize the recovered conditions with time. IR thermography is widely used for diagnostics and to validate those systems, by comparing thermograms before and after the installation up to fully operational conditions. In this paper, an analytical procedure aimed at optimizing the processing and the interpretation of thermograms is proposed. It is based on the analysis of 220 thermograms captured on 33 masonry buildings in Italy, whose results were also compared with gravimetric tests, where available. Numerical indexes were computed based on statistical analyses of the relative thermal gradients. The research also pointed out the need of specific protocols for the correct application of IR thermography onsite, so that a reliable comparison among the results can be carried out to validate the effectiveness of systems aimed at protecting the buildings
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