THE USE OF GIS FOR THE APPLICATION OF THE PHENOMENOLOGICAL APPROACH TO THE SEISMIC RISK ANALYSIS: THE CASE OF THE ITALIAN FORTIFIED ARCHITECTURE

The present paper proposes the use of GIS for the application of the so-called phenomenological approach to the analysis of the seismic behaviour of historical buildings. This approach is based on the awareness that the different masonry building typologies are characterized by different, recurring vulnerabilities. Thus, the observation and classification of the real damage is seen as the first step for recognizing and classifying these vulnerabilities, in order to plan focused preventive interventions. For these purposes, the GIS has proven to be a powerful instrument to collect and manage this type of information on a large number of cases. This paper specifically focuses on the application of the phenomenological approach to the analysis of the seismic behaviour of fortified buildings, including castles, fortresses, citadels, and all the typical historical constructions characterized by the presence of massive towers and defensive walls. The main earthquakes which struck Italy in the last 40 years (up to the recent Central Italy seismic swarm) were taken into consideration and described by means of shake maps. A previously published work has been continued with the addition of new data and some improvements, including a specific symbology for the description of building typologies and conservation status on the maps, the indications of damage levels and the comparison between shake maps in terms of pga and in terms of pseudo-acceleration. The increase in knowledge obtained and the broader frame given by the analysis of the data are here directed to the primary aim of cultural heritage preservation

Dynamic Identification of Large Thin Shell Structures in Concrete

The paper presents the results of a recent testing campaign carried out on the vaulted structures built by Pier Luigi Nervi in Torino Esposizioni. Nervi’s halls are a spatial structure masterpiece, admired for their daring and innovative conception. The technological achievements of the 20th century have allowed conceiving unprecedented large scale and complex structures. However, the experimental nature of numerous innovative structural and spatial configurations adopted by the designers of the time have revealed over time intrinsic fragilities that, when neglected, have threatened their long-term structural integrity. In addition, 20th century’s structures were usually conceived without accounting for seismic actions, but only for static configurations, in accordance with the technical standards of the time. Therefore, it is of crucial importance to assess the dynamic behavior of these structures to understand their vulnerability and plan their correct preservation measures. Due to its complex configuration, the setup of dynamic testing campaign for Hall B built by Nervi presented many challenges, including: i) the complex optimization problems due to the spatial characters of the vaulted structure; ii) the possible effects of damage degradation or anomalies. The aims of this investigation were to investigate the behavior of historical spatial structures to seismic actions; and to detect the presence of possible structural anomalies

DOCUMENTING COMPLEXITY FOR THE 20TH CENTURY HERITAGE: THE ENRICHED 3D MODELS OF THE TURIN EXPOSITION NERVI’S HALLS DIGITIZATION

Great attention is increasingly paid to the heritage belonging to the XX century, particularly for the spatial structures made of concrete, that are a significant trait of this modern movement architecture. Since they demand today urgent conservation plans sustaining their deterioration, the multidisciplinary researches should devotes a profound investigations for tailored approaches providing a clear indication of best practices and recommendation for correct 3D documentation, information management and structural assessment and monitoring. In this framework, the Geomatics approaches are advancing the interests toward the multi-scale and multi-sensor digitization and for supporting management of complex information in enriched 3D models. The iconic halls B and C in Torino Esposizioni (Italy), designed by Pier Luigi Nervi, is the case study presented. It was recently awarded by the Getty Keeping it Modern grant. The multi-disciplinary research conducted, still in progress, focuses a particularly into the investigation of the structural analysis and consistency of ferrocement elements of the vaulted system finalized to the structural condition assessment. Here the role of multi-scale and multi-sensor 3D models is investigated, such as the development of a digital twin of the halls as a starting point to create an enriched informative system. The reconstruction of this model particularly considering the large extension and the complexity of the spaces, is addressed to works as a collector of 3D multi-sensor data and information related to the diagnostic investigation on structural health monitoring for the durability of ferrocement elements

Documenting Complexity for the 20TH Century Heritage: the Enriched 3d Models of the Turin Exposition Nervi's Halls Digitization

Abstract. Great attention is increasingly paid to the heritage belonging to the XX century, particularly for the spatial structures made of concrete, that are a significant trait of this modern movement architecture. Since they demand today urgent conservation plans sustaining their deterioration, the multidisciplinary researches should devotes a profound investigations for tailored approaches providing a clear indication of best practices and recommendation for correct 3D documentation, information management and structural assessment and monitoring. In this framework, the Geomatics approaches are advancing the interests toward the multi-scale and multi-sensor digitization and for supporting management of complex information in enriched 3D models. The iconic halls B and C in Torino Esposizioni (Italy), designed by Pier Luigi Nervi, is the case study presented. It was recently awarded by the Getty Keeping it Modern grant. The multi-disciplinary research conducted, still in progress, focuses a particularly into the investigation of the structural analysis and consistency of ferrocement elements of the vaulted system finalized to the structural condition assessment. Here the role of multi-scale and multi-sensor 3D models is investigated, such as the development of a digital twin of the halls as a starting point to create an enriched informative system. The reconstruction of this model particularly considering the large extension and the complexity of the spaces, is addressed to works as a collector of 3D multi-sensor data and information related to the diagnostic investigation on structural health monitoring for the durability of ferrocement elements

Challenges in the reuse and upgrade of Pier Luigi Nervi 's structures

The paper presents the overall objectives of a funded research program for the development of a Conservation Plan (CP) for the two halls by Pier Luigi Nervi of the Turin Exhibition Center. The Turin Exhibition Center was conceived immediately after the Second World War to host primarily the annual Automobile Show, in connection with the presence in Turin of the FIAT motor company. The two main pavilions of the Center (Halls B and C) are outstanding examples of a pioneering use, of new advanced methods in reinforced concrete construction, combining innovative prefabrication procedures and the re-invention by Nervi of ferrocement, used to form extremely thin elements. The CP is expected to push and contribute to the preservation of the halls designed and built by Nervi, with special emphasis on structural and seismic vulnerability aspects, also due to concerns raised on the durability of concrete materials and technologies. Re-using these buildings entails the challenge to guarantee new extended service life to concrete structures built many decades ago and faces the need for a seismic assessment of these structures, in compliance to recent Italian standards

GIS Methodologies for the Management of Seismic Risk and the Damage Prevention on Masonry-Built Heritage

The Geographic Information System (GIS) is increasingly used in the scientific field for the management and conservation of built heritage. The present paper proposes a GIS methodology for the collection and analysis of the data related to the seismic risk and for the management of damage prevention interventions on masonry architectural assets, based on the empirical approach. Indeed, starting from the observation of real damage, that occurred after the recent Italian earthquakes, it was possible to collect a large amount of data, which has been organized and queried using the GIS tool. This methodology was tested on two different architectural typologies, designing two different databases: protruding elements and fortified architectures. This proactive tool allowed both the correlation between constructive features and damage mechanisms, through statistical analyses, and the comparison of the damage levels with the seismic action of the site, through the introduction in the GIS of the shake-maps, to identify the empirical fragility curves, which represent the expected damage, depending on the seismic action. Then, these functions were applied to an area without earthquake damage, using the seismic actions provided by the hazard map. This methodology allowed the identification of the assets most at risk in case of future seismic events, on a large scale. Knowing the vulnerabilities of the heritage means being able to act preventively, with planned conservation strategies, optimizing the management of economic resources, and minimizing invasive interventions

Analytical Relation Between Natural Frequency and Spectral Entropy in Information Theory of Single Degree of Freedom Systems

The eighth (and last) axiom of Structural Health Monitoring (SHM) states that damage increases the complexity of a system. After its introduction, several methods to measure complexity have been explored in the scientific literature. Among these, entropy measures demonstrate to be very straightforward to apply, with a relatively simple concept behind them. Thus, based on this feature, researchers proposed damage identification methodology in several branches of research, such as mechanical engineering, civil engineering, etc. In this work, the authors present an analytical study on the dependency of spectral entropy measures from the modal characteristics of a structural system, showing that an analytical relation exists for what concerns a Single Degree of Freedom (SDoF) system. A comparison between spectral entropy of different physical quantities (displacements, velocity, accelerations, etc.) is discussed for their use in SHM. Finally, different contributions of variation in entropy (i.e., due to external sources and structural properties) are analysed to better understand the causes of these perturbations. The work is of particular interest for cultural heritage structures since many of these are characterised by the presence of protruding elements, most of the time assimilable to SDoF systems (e.g., lanterns, belfries, pinnacles, etc.), when their dynamic is analysed relatively to their base movement

Integration of Digital Image Correlation in Flexural Tests for the Corrosion Evaluation of Ferrocement Plates

Ferrocement is a thin reinforced cementitious composites of hydraulic cement mortar with layers of wire steel mesh, which has been widely used in the roofing systems in major 20th-century architectures. However, few studies have analyzed its durability for preservation purposes and stiffens time-dependency evolution. In the present paper the results of a recent testing campaign on ferrocement specimens subjected to a corrosive environment are presented. The experimental campaign in monitored by 3D-Digital Image Correlation (DIC) signal processing. In particular, the external evidence obtained by the reconstruction of the strain field may be directly correlated with the 3-D localization of the microraking formation in the tested specimen obtained by AE detection. The aim was to assess the behavior of historical ferrocement (used by Pier Luigi Nervi in his constructions) and its durability for identifying the best procedures to protect and preserve it