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  • 1
    Publication Date: 2018-03-01
    Description: Several non-destructive (ND) techniques are presented as a tool for the evaluation of the conservation state of carbonate building materials of the “Palazzo di Città”, a historic building in the centre of Cagliari, a town in Italy. In this study, considering both the nature of the building materials and the constructive types of the investigated architectural structure, ultrasonic investigations were carried at 54 kHz. The ultrasonic measurements were performed both in the laboratory and in situ using the portable ultrasonic non-destructive digital indicating tester (PUNDIT Lab plus©) by Proceq (Schwerzenbach, Switzerland). The ultrasonic measurements were integrated by a petrographical and petrophysical study of the investigated stone materials in order to correlate their petrographical-petrophysical features with the elastic ones. A further implementation was carried out comparing elasto-mechanical and petrographical-petrophysical features of the investigated carbonate materials with surface geometric anomalies computed by means of the architectonic terrestrial laser scanner (TLS) application. In particular, we used a Leica HDS-6200 TLS to study the complex shape of some artifacts from the “Palazzo di Città” monumental compound. A multi station approach was adopted in order to acquire more than 180 million points by performing 30 high resolution structured scans. After TLS data elaboration with JRC 3D Reconstructor® software, the 3D model of the buildings together with morphological anomalies of some artifacts were computed in order to highlight the zones where the deformation was more evident.
    Description: Regione Autonoma della Sardegna
    Description: Published
    Description: 71-84
    Description: 4T. Sismologia, geofisica e geologia per l'ingegneria sismica
    Description: JCR Journal
    Keywords: Non-destructive testing ; Ultrasonic measurements ; Terrestrial laser scanner ; Petrographical study ; Cultural heritage ; Cultural Heritage ; Petrographical study ; Non-destructive testing
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 2
    Publication Date: 2023-03-20
    Description: Here, an avant-garde study of three ancient Doric columns of the precious, ancient Romanesque church of Saints Lorenzo and Pancrazio in the historical town center of Cagliari (Italy) is presented based on the integrated application of different non-destructive testing methods. The limitations of each methodology are overcome by the synergistic application of these methods, affording an accurate, complete 3D image of the studied elements. Our procedure begins with a macroscopic in situ analysis to provide a preliminary diagnosis of the conditions of the building materials. The next step is laboratory tests, in which the porosity and other textural characteristics of the carbonate building materials are studied by optical and scanning electron microscopy. After this, a survey with a terrestrial laser scanner and close-range photogrammetry is planned and executed to produce accurate high-resolution 3D digital models of the entire church and the ancient columns inside. This was the main objective of this study. The high-resolution 3D models allowed us to identify architectural complications occurring in historical buildings. The 3D reconstruction with the above metric techniques was indispensable for planning and carrying out the 3D ultrasonic tomography, which played an important role in detecting defects, voids, and flaws within the body of the studied columns by analyzing the propagation of the ultrasonic waves. The high-resolution 3D multiparametric models allowed us to obtain an extremely accurate picture of the conservation state of the studied columns in order to locate and characterize both shallow and internal defects in the building materials. This integrated procedure can aid in the control of the spatial and temporal variations in the materials’ properties and provides information on the process of deterioration in order to allow adequate restoration solutions to be developed and the structural health of the artefact to be monitored.
    Description: Published
    Description: 3098
    Description: 5T. Sismologia, geofisica e geologia per l'ingegneria sismica
    Description: JCR Journal
    Keywords: close-range photogrammetry ; terrestrial laser scanner ; 3D digital models ; 3D ultrasonic tomography ; petrographic analyses ; carbonate materials ; 05.04. Instrumentation and techniques of general interest
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 3
    Publication Date: 2024-05-16
    Description: Abstract: Non-invasive techniques, such as close-range photogrammetry (CRP) and 3D ultrasonic tomography complemented with optical and scanning electron microscopy and mercury porosimetry, were applied to characterize the carbonate rock samples of the Calcari di Cagliari formation. The integrated approach started with the computation of high-resolution 3D models of the carbonate samples using the CRP technique to produce 3D high-resolution models texturized both with natural colors and intensity. Starting from the 3D models from previous techniques, a 3D ultrasonic tomography on each rock sample was accurately planned and carried out in order to detect the elastic properties of such rocks and relate them to textural heterogeneity or internal defects. The results indicate that the relationship between longitudinal velocity and rock properties is complex even in the same carbonate formation. Understanding the relationship between the geomatic and geophysical responses in the investigated rock properties, such as textural characteristics and especially structure and geometry of pores, type of pores, tortuosity and cementing material, is important for many practical applications and especially in the diagnostic process of the conservation state of monumental structures. The integration of the above non-invasive techniques complemented by petrographical–petrophysical data proved to be a powerful method to associate each lithotype with a different susceptibility to degradation. The results presented in this paper demonstrate that the proposed integrated use of complementary methodologies would guarantee the reproducibility of the measurements both at the laboratory and field scale for the monitoring in time of the rock condition while giving a useful contribution in making decisions on an appropriate remedial strategy.
    Description: Published
    Description: 501
    Description: OSA5: Energia e georisorse
    Description: JCR Journal
    Keywords: carbonate rocks ; petrographic data ; photogrammetry ; ultrasonic tomography ; integrated interpretation ; 05.04. Instrumentation and techniques of general interest
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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