Within the framework of a European Commission project entitled Cultural HEritage against Flood (C... more Within the framework of a European Commission project entitled Cultural HEritage against Flood (CHEF), a research was carried out in Milan on full-scale stone and brick masonry models by means of a simulated flood to investigate the effects of floods on historic and masonry buildings. The objective was to evaluate the post-flood moisture content and the drying process through non-destructive or minor-destructive techniques. Several non-destructive testing (NDT) were applied (thermography, sonic tests, radar) and were compared with the powder drilling test. Thermography and radar tests were the most useful; the attention is here more concentrated on radar tests which revealed interesting results. A high frequency GPR system was used to perform measurements on selected points of the models at selected intervals during the drying period. Radar velocity, radar amplitude in transmission and in reflection mode, radar waveform distortion and spectra were analyzed as a function of time after flooding and were compared to moisture content assessed by the powder drilling method. Measurements of radar velocity and radar waveform distortion were found meaningful and in agreement with the expected drying process.
After the earthquake that stroke the city of L’Aquila during the night of April 6th 2009, many hi... more After the earthquake that stroke the city of L’Aquila during the night of April 6th 2009, many historical buildings at the city centre were severly damaged. Nevertheless many others survived the seismic event with only local damages, showing a good mechanical behaviour against vertical and horizontal actions. In order to continue preserving these buildings, a careful investigation is necessary before applying any repair technique, new or traditional to understand the past design practices for building durable and safe structures. In order to understand the structural behaviour of the church of St. Biagio in L’aquila, an extensive diagnostic investigation based on non-destructive and minor destructive techniques was carried out by the authors. The paper describes mainly the applied methodology which can produce some guidelines to be followed in the future study of other Cultural Heritage (C. H.) buildings hit by the earthquake.
In the framework of the DISWall research project, funded by the European Commission, various inno... more In the framework of the DISWall research project, funded by the European Commission, various innovative construction systems for load and non-load-bearing reinforced masonry walls have been developed and have been subjected to extensive laboratory testing and analytical studies. One of the project aims was to calibrate existing methods for non-destructive testing on modern reinforced masonry buildings. Thus, two specimens featuring known defects affecting reinforcements were built making use of perforated clay units. Subsequently radar, sonic and ultrasonic techniques were employed to investigate the specimens, with the intention of detecting reinforcements and defects. The proposed Non-Destructive Techniques (NDT) were applied at different stages of the construction, in order to evaluate their effectiveness in solving the identified testing problems. Several difficulties were encountered due to non sufficient sampling rate as well as to the presence of holes, concerning respectively sonic and ultrasonic measurements. However, some interesting results were obtained, in particular by means of radar tests, and are discussed in the present contribution.
We discuss the potential of Ground Penetrating Radar (GPR) for tree root mapping by presenting th... more We discuss the potential of Ground Penetrating Radar (GPR) for tree root mapping by presenting the results from three recent studies performed in different sites with secular trees. Depending on the survey area, we discuss the use of two different hardware solutions to perform high density 3D surveys: a single antenna (500MHz or 1GHz) in combination with a PSG (Pad System for Georadar) or a 600MHz array system (IDS Stream C). The results show that GPR method can be an effective tool to map the roots. The approximate extent of the soil volume hosting most of the roots can be easily interpreted after applying a standard data processing sequence. However, advanced image interpretation remains an open issue and, in case a detailed root net reconstruction is needed, the cost of the interpretation phase prevails over the costs of acquisitions and data processing and can significantly affect the overall project costs. Algorithms for automatic root drawing would be the solution but the reliability of such root maps is still to be validated
The sonic pulse velocity method is used for preliminarily investigations on several masonry struc... more The sonic pulse velocity method is used for preliminarily investigations on several masonry structures, characterized by different typologies (stone, clay bricks) and quality of materials (rubble, ashlars, regular, inhomogeneous combinations, etc..). In the paper, the elaboration of results of over ten different historical contexts and their possible comparisons allowed to qualify the related typologies on the basis of the elaborated sonic velocities. Both direct and indirect tests are taken into account, as well as tomographic evaluations, to clarify specific constructive aspects of typical historic masonry structures. Results are useful to provide materials specification in the subsequent assessment analyses, by calibrating structural models and in the phase of interventions choice and effectiveness evaluations. Résumé La méthode de la vitesse des impulsions soniques est utilisée pour la caractérisation préliminaire de maçonneries de différentes typologies (en pierre, briques) et qualité des matériaux. La recherche considère les résultats des essais conduits sur plus de dix différentes structures historiques. La comparaison des résultats permet de qualifier les différentes typologies analysées sur la base de l'élaboration des vitesses soniques. La méthodologie considère les mesures directe et indirecte, ainsi que des tomographies, pour essayer de préciser les aspects constructifs et historiques des structures de maçonnerie analysées. Les résultats proposés permettent une spécification des matériaux dans la phase d'évaluation structurelle, la calibration des modèles structurels, dans la phase de choix des interventions et pour évaluer leur efficacité.
This work is based on the assumption that a resistivity meter can effectively monitor water satur... more This work is based on the assumption that a resistivity meter can effectively monitor water saturation in earth levees and can be used as a warning system when saturation exceeds the expected seasonal maxima. We performed time-lapse ERT measurements to assess the capability of this method to detect areas where seepage is critical. These measurements were also very useful to design a prototype monitoring system with remarkable savings by customizing the specifications according to field observations. The prototype consists of a remotely controlled low-power resistivity meter with a spread of 48 stainless steel 20 × 20 cm plate electrodes buried at half-meter depth. We deployed the newly-designed permanent monitoring system on a critical levee segment. A weather station and an ultrasonic water level sensor were also installed in order to analyse the correlation of resistivity with temperature, rainfalls and water level seasonal variations. The preliminary analysis of the monitoring data shows that the resistivity maps follow a very reasonable trend related with the saturation/drying cycle of the levee caused by the seasonal variations of the water level in the irrigation channel. Sharp water level changes cause delayed and smooth resistivity variations. Rainfalls and, to a lesser extent, temperature seem to have an influence on the collected data but effects are apparently negligible beyond 1 m depth. The system is currently operating and results are continuously monitored.
In the framework of the DISWall research project, funded by the European Commission, quality asse... more In the framework of the DISWall research project, funded by the European Commission, quality assessment procedures for modern reinforced masonry buildings, involving nondestructive test methods, were performed. Different testing techniques were applied on two reinforced masonry systems, based on concentrated vertical reinforcement and on the use of perforated clay units. This contribution focuses on results obtained by radar and sonic techniques, applied in laboratory on two masonry specimens which were built including known defects in the masonry. The tests were also carried out on-site, on real walls of a selected case study. Among the various techniques, dynamic tests were also performed. Their results are reported in Mosele, da Porto, Modena (2008), of the present conference. Résumé Dans le cadre du projet de recherche DISWall, financé par la Commission Européenne, ont été mises en oeuvre des procédures de contrôle de la qualité de la construction moderne en maçonnerie armée, fondées sur l'usage des techniques non-destructives. Diverses techniques d'épreuve ont été appliquées sur deux systèmes différents en maçonnerie armée : avec renforcement vertical ciblé, et, basé sur l'usage de blocs de briques creuses. Sont présentés dans cette contribution, les résultats des méthodes radar et soniques appliquées dans le laboratoire sur deux spécimens de maçonnerie construits avec une série de défauts. Les mêmes méthodes ont été répétées in-situ, sur les panneaux de maçonnerie armée d'un bâtiment. Parmi les différentes techniques appliquées, des tests dynamiques ont également été effectués. Les résultats sont présentés dans Mosele, da Porto, Modena (2008), à cette conférence.
In the framework of the DISWall research project, funded by the European Commission, we have been... more In the framework of the DISWall research project, funded by the European Commission, we have been working on the development of quality assessment procedures for modern reinforced masonry buildings based on non‐destructive testing methods. We considered two specific ...
In 2011, the engineer Giuseppe Albano studied the geometry and state of conservation of the struc... more In 2011, the engineer Giuseppe Albano studied the geometry and state of conservation of the structures of the vault system of the Sala delle Asse to assess any damage and instabilities in the room and proposed a series of studies and monitoring for the cracks that had been detected on the extrados of the lower vault and on the vertical structures, with the aim of identifying any movement that might be un\uadder way. Currently, a diagnostic campaign is in progress, targeted towards understanding the build\uad ing technique and structural behaviour of the vault system. Radar studies were conducted to reconstruct the stratigraphy of the system comprising the lunetted cloister vault, the depressed arch cloister vault above and the floor of the room on the upper floor. Other radar studies were conducted to characterize the raised wall structures, which are of notable thickness (even as much as aver 2.5 m) and to identify cavities and a flue that runs along the full height of the north-east wall. A topographical/diagnostic laser scanner survey will make it possible to reveal the critical points of the structures and types of instability and provide understanding of the dynamics of the crack pattern. The stratigraphic reading will make it possible to codify the archaeological sequence of the built structure, the deterioration and state of damage (the contribution The Diagnostic Survey: The Sala delle Asse and its Context in the present volume).The need to speed Up the time spent collecting information that would be useful for safeguarding and protecting the room forced the immediate installation of a system far monitoring cracks based on the information available at the time, which derived from a preliminary survey and the results of thermographic studies (see the contribution The Preliminary Thermo-Hygrometric Research and Environmental Monitoring of the Sala delle Asse in this volume), which revealed a few structural cracks. It will be possible to review or integrate the arrangement of the transducers based on the results of the above-described survey
The earthquake occurred on the 6th of April 2009 in the Abruzzo Region of Italy seriously hit the... more The earthquake occurred on the 6th of April 2009 in the Abruzzo Region of Italy seriously hit the Cultural Heritage (C.H.) patrimony with major destructive effects on l’Aquila, a city of 70,000 inhabitants with the size and the historical and strategic importance of the capital of the Region. The emergency activities to protect the C.H. have been developed following two parallel levels: (i) damage survey and (ii) design and implementation of temporary safety measures. The organization of emergency actions was managed by a centralized structure, the so-called Function 15 “Protection of Cultural Heritage” directed by a Special Commissioner. The structure coordinated the on-site surveys of protected buildings and the design and implementation of temporary safety measures. Several Italian Universities during and after these first emergency actions were invited by the Commissioner to work on selected Case Histories: the aim was on the one hand to provide a first interpretation of the observed damages and on the other hand to define some guidelines for a higher level of investigation
2012 14th International Conference on Ground Penetrating Radar (GPR), Jun 1, 2012
ABSTRACT Early detection of fractures and internal defects can help quarry owners in cutting quar... more ABSTRACT Early detection of fractures and internal defects can help quarry owners in cutting quarrying costs and reducing the amount of waste products. Valuable stones used in construction industry such as marble, porphyry, granite, travertine, are usually extracted from quarries by cutting blocks whose size normally varies between 5 and 15 m3. Transportation of these blocks from quarries, often located at high altitudes in mountainous environments, down to the headquarters of the stone industry where big machines are installed to transform the big size blocks into slabs or small size stones, can be quite expensive. Money could be saved by checking on-site the big size blocks with NDT methods able to detect internal fractures and other defects (voids, clay inclusions, etc.). A detailed map of fracture extension and orientation can be also very profitable in optimizing the production line. For example, the final destination of a block (i.e., production of slabs rather than small size blocks or other) and the orientation of the cutting planes can be more properly assigned. Currently, Ground Penetrating Radar is the most promising method for this type of application. It can be applied on-site, it can generate high resolution 3D reconstructions of fractures and defects, quasi-real-time results are feasible. Thus, it can be a cost-effective tool, worth being introduced into the quarry industry. To evaluate the potential of this technology for the quarry industry we have been testing the method on marble and porphyry blocks from a couple of quarries belonging to the Brescia stone district (North Italy). Results are very encouraging: all type of defects and fractures that might have an impact on the production line can be detected by 3D surveying the block with a 2GHz GPR system. A dual-polarized antenna is a plus that makes acquisitions faster and easier. Data processing must include two-dimensional filtering to cancel the artifacts generated by side reflections and 3D- migration to generate accurate reconstructions of the target geometries.
3rd Asia Pacific Meeting on Near Surface Geoscience & Engineering, 2020
We discuss the potential of Ground Penetrating Radar (GPR) for tree root mapping by presenting th... more We discuss the potential of Ground Penetrating Radar (GPR) for tree root mapping by presenting the results from three recent studies performed in different sites with secular trees. Depending on the survey area, we discuss the use of two different hardware solutions to perform high density 3D surveys: a single antenna (500MHz or 1GHz) in combination with a PSG (Pad System for Georadar) or a 600MHz array system (IDS Stream C). The results show that GPR method can be an effective tool to map the roots. The approximate extent of the soil volume hosting most of the roots can be easily interpreted after applying a standard data processing sequence. However, advanced image interpretation remains an open issue and, in case a detailed root net reconstruction is needed, the cost of the interpretation phase prevails over the costs of acquisitions and data processing and can significantly affect the overall project costs. Algorithms for automatic root drawing would be the solution but the reliability of such root maps is still to be validated
In 2011, the engineer Giuseppe Albano studied the geometry and state of conservation of the struc... more In 2011, the engineer Giuseppe Albano studied the geometry and state of conservation of the structures of the vault system of the Sala delle Asse to assess any damage and instabilities in the room and proposed a series of studies and monitoring for the cracks that had been detected on the extrados of the lower vault and on the vertical structures, with the aim of identifying any movement that might be un\uadder way. Currently, a diagnostic campaign is in progress, targeted towards understanding the build\uad ing technique and structural behaviour of the vault system. Radar studies were conducted to reconstruct the stratigraphy of the system comprising the lunetted cloister vault, the depressed arch cloister vault above and the floor of the room on the upper floor. Other radar studies were conducted to characterize the raised wall structures, which are of notable thickness (even as much as aver 2.5 m) and to identify cavities and a flue that runs along the full height of the north-east wall. A topographical/diagnostic laser scanner survey will make it possible to reveal the critical points of the structures and types of instability and provide understanding of the dynamics of the crack pattern. The stratigraphic reading will make it possible to codify the archaeological sequence of the built structure, the deterioration and state of damage (the contribution The Diagnostic Survey: The Sala delle Asse and its Context in the present volume).The need to speed Up the time spent collecting information that would be useful for safeguarding and protecting the room forced the immediate installation of a system far monitoring cracks based on the information available at the time, which derived from a preliminary survey and the results of thermographic studies (see the contribution The Preliminary Thermo-Hygrometric Research and Environmental Monitoring of the Sala delle Asse in this volume), which revealed a few structural cracks. It will be possible to review or integrate the arrangement of the transducers based on the results of the above-described survey
Proceedings of the 15th International Conference on Ground Penetrating Radar, 2014
The 19th century restoration works of the Basilica of Sant'Andrea in Mantua consisted of impo... more The 19th century restoration works of the Basilica of Sant'Andrea in Mantua consisted of important modifications of pronaos and facade. According to historical documents, the use of metal reinforcements was planned to tie the facade with the counter-facade but designs and details are missing and since no external evidences of the tie-rods can be observed, the existence of these reinforcements was a fundamental open issue. The problem has been recently addressed with a GPR survey. Some tie-rods have been confirmed. The location of some of them has been problematic because of plaster decorations that reduced the survey area to narrow corridors. The dual-polarization was a benefit because some reinforcements, oriented parallel to the survey corridor, were detected only by the parallel-broadside polarization. In addition, for the exact location of these elements, 3D migration was needed because the reflection was generated out-of-plane. Some other unexpected reinforcements were also detected within the counter-facade wall. The complex geometry of these reinforcements was finally understood by composing the results of GPR investigations on orthogonal faces of the counter-facade. However, a tricky question arose on one side of the wall where an unexpected anomaly in GPR response seemed to reveal the presence of an additional set of metal bars. Again the dual-polarization was essential to exclude this misinterpretation and to understand the real origin of these unexpected signals.
Within the framework of a European Commission project entitled Cultural HEritage against Flood (C... more Within the framework of a European Commission project entitled Cultural HEritage against Flood (CHEF), a research was carried out in Milan on full-scale stone and brick masonry models by means of a simulated flood to investigate the effects of floods on historic and masonry buildings. The objective was to evaluate the post-flood moisture content and the drying process through non-destructive or minor-destructive techniques. Several non-destructive testing (NDT) were applied (thermography, sonic tests, radar) and were compared with the powder drilling test. Thermography and radar tests were the most useful; the attention is here more concentrated on radar tests which revealed interesting results. A high frequency GPR system was used to perform measurements on selected points of the models at selected intervals during the drying period. Radar velocity, radar amplitude in transmission and in reflection mode, radar waveform distortion and spectra were analyzed as a function of time after flooding and were compared to moisture content assessed by the powder drilling method. Measurements of radar velocity and radar waveform distortion were found meaningful and in agreement with the expected drying process.
After the earthquake that stroke the city of L’Aquila during the night of April 6th 2009, many hi... more After the earthquake that stroke the city of L’Aquila during the night of April 6th 2009, many historical buildings at the city centre were severly damaged. Nevertheless many others survived the seismic event with only local damages, showing a good mechanical behaviour against vertical and horizontal actions. In order to continue preserving these buildings, a careful investigation is necessary before applying any repair technique, new or traditional to understand the past design practices for building durable and safe structures. In order to understand the structural behaviour of the church of St. Biagio in L’aquila, an extensive diagnostic investigation based on non-destructive and minor destructive techniques was carried out by the authors. The paper describes mainly the applied methodology which can produce some guidelines to be followed in the future study of other Cultural Heritage (C. H.) buildings hit by the earthquake.
In the framework of the DISWall research project, funded by the European Commission, various inno... more In the framework of the DISWall research project, funded by the European Commission, various innovative construction systems for load and non-load-bearing reinforced masonry walls have been developed and have been subjected to extensive laboratory testing and analytical studies. One of the project aims was to calibrate existing methods for non-destructive testing on modern reinforced masonry buildings. Thus, two specimens featuring known defects affecting reinforcements were built making use of perforated clay units. Subsequently radar, sonic and ultrasonic techniques were employed to investigate the specimens, with the intention of detecting reinforcements and defects. The proposed Non-Destructive Techniques (NDT) were applied at different stages of the construction, in order to evaluate their effectiveness in solving the identified testing problems. Several difficulties were encountered due to non sufficient sampling rate as well as to the presence of holes, concerning respectively sonic and ultrasonic measurements. However, some interesting results were obtained, in particular by means of radar tests, and are discussed in the present contribution.
We discuss the potential of Ground Penetrating Radar (GPR) for tree root mapping by presenting th... more We discuss the potential of Ground Penetrating Radar (GPR) for tree root mapping by presenting the results from three recent studies performed in different sites with secular trees. Depending on the survey area, we discuss the use of two different hardware solutions to perform high density 3D surveys: a single antenna (500MHz or 1GHz) in combination with a PSG (Pad System for Georadar) or a 600MHz array system (IDS Stream C). The results show that GPR method can be an effective tool to map the roots. The approximate extent of the soil volume hosting most of the roots can be easily interpreted after applying a standard data processing sequence. However, advanced image interpretation remains an open issue and, in case a detailed root net reconstruction is needed, the cost of the interpretation phase prevails over the costs of acquisitions and data processing and can significantly affect the overall project costs. Algorithms for automatic root drawing would be the solution but the reliability of such root maps is still to be validated
The sonic pulse velocity method is used for preliminarily investigations on several masonry struc... more The sonic pulse velocity method is used for preliminarily investigations on several masonry structures, characterized by different typologies (stone, clay bricks) and quality of materials (rubble, ashlars, regular, inhomogeneous combinations, etc..). In the paper, the elaboration of results of over ten different historical contexts and their possible comparisons allowed to qualify the related typologies on the basis of the elaborated sonic velocities. Both direct and indirect tests are taken into account, as well as tomographic evaluations, to clarify specific constructive aspects of typical historic masonry structures. Results are useful to provide materials specification in the subsequent assessment analyses, by calibrating structural models and in the phase of interventions choice and effectiveness evaluations. Résumé La méthode de la vitesse des impulsions soniques est utilisée pour la caractérisation préliminaire de maçonneries de différentes typologies (en pierre, briques) et qualité des matériaux. La recherche considère les résultats des essais conduits sur plus de dix différentes structures historiques. La comparaison des résultats permet de qualifier les différentes typologies analysées sur la base de l'élaboration des vitesses soniques. La méthodologie considère les mesures directe et indirecte, ainsi que des tomographies, pour essayer de préciser les aspects constructifs et historiques des structures de maçonnerie analysées. Les résultats proposés permettent une spécification des matériaux dans la phase d'évaluation structurelle, la calibration des modèles structurels, dans la phase de choix des interventions et pour évaluer leur efficacité.
This work is based on the assumption that a resistivity meter can effectively monitor water satur... more This work is based on the assumption that a resistivity meter can effectively monitor water saturation in earth levees and can be used as a warning system when saturation exceeds the expected seasonal maxima. We performed time-lapse ERT measurements to assess the capability of this method to detect areas where seepage is critical. These measurements were also very useful to design a prototype monitoring system with remarkable savings by customizing the specifications according to field observations. The prototype consists of a remotely controlled low-power resistivity meter with a spread of 48 stainless steel 20 × 20 cm plate electrodes buried at half-meter depth. We deployed the newly-designed permanent monitoring system on a critical levee segment. A weather station and an ultrasonic water level sensor were also installed in order to analyse the correlation of resistivity with temperature, rainfalls and water level seasonal variations. The preliminary analysis of the monitoring data shows that the resistivity maps follow a very reasonable trend related with the saturation/drying cycle of the levee caused by the seasonal variations of the water level in the irrigation channel. Sharp water level changes cause delayed and smooth resistivity variations. Rainfalls and, to a lesser extent, temperature seem to have an influence on the collected data but effects are apparently negligible beyond 1 m depth. The system is currently operating and results are continuously monitored.
In the framework of the DISWall research project, funded by the European Commission, quality asse... more In the framework of the DISWall research project, funded by the European Commission, quality assessment procedures for modern reinforced masonry buildings, involving nondestructive test methods, were performed. Different testing techniques were applied on two reinforced masonry systems, based on concentrated vertical reinforcement and on the use of perforated clay units. This contribution focuses on results obtained by radar and sonic techniques, applied in laboratory on two masonry specimens which were built including known defects in the masonry. The tests were also carried out on-site, on real walls of a selected case study. Among the various techniques, dynamic tests were also performed. Their results are reported in Mosele, da Porto, Modena (2008), of the present conference. Résumé Dans le cadre du projet de recherche DISWall, financé par la Commission Européenne, ont été mises en oeuvre des procédures de contrôle de la qualité de la construction moderne en maçonnerie armée, fondées sur l'usage des techniques non-destructives. Diverses techniques d'épreuve ont été appliquées sur deux systèmes différents en maçonnerie armée : avec renforcement vertical ciblé, et, basé sur l'usage de blocs de briques creuses. Sont présentés dans cette contribution, les résultats des méthodes radar et soniques appliquées dans le laboratoire sur deux spécimens de maçonnerie construits avec une série de défauts. Les mêmes méthodes ont été répétées in-situ, sur les panneaux de maçonnerie armée d'un bâtiment. Parmi les différentes techniques appliquées, des tests dynamiques ont également été effectués. Les résultats sont présentés dans Mosele, da Porto, Modena (2008), à cette conférence.
In the framework of the DISWall research project, funded by the European Commission, we have been... more In the framework of the DISWall research project, funded by the European Commission, we have been working on the development of quality assessment procedures for modern reinforced masonry buildings based on non‐destructive testing methods. We considered two specific ...
In 2011, the engineer Giuseppe Albano studied the geometry and state of conservation of the struc... more In 2011, the engineer Giuseppe Albano studied the geometry and state of conservation of the structures of the vault system of the Sala delle Asse to assess any damage and instabilities in the room and proposed a series of studies and monitoring for the cracks that had been detected on the extrados of the lower vault and on the vertical structures, with the aim of identifying any movement that might be un\uadder way. Currently, a diagnostic campaign is in progress, targeted towards understanding the build\uad ing technique and structural behaviour of the vault system. Radar studies were conducted to reconstruct the stratigraphy of the system comprising the lunetted cloister vault, the depressed arch cloister vault above and the floor of the room on the upper floor. Other radar studies were conducted to characterize the raised wall structures, which are of notable thickness (even as much as aver 2.5 m) and to identify cavities and a flue that runs along the full height of the north-east wall. A topographical/diagnostic laser scanner survey will make it possible to reveal the critical points of the structures and types of instability and provide understanding of the dynamics of the crack pattern. The stratigraphic reading will make it possible to codify the archaeological sequence of the built structure, the deterioration and state of damage (the contribution The Diagnostic Survey: The Sala delle Asse and its Context in the present volume).The need to speed Up the time spent collecting information that would be useful for safeguarding and protecting the room forced the immediate installation of a system far monitoring cracks based on the information available at the time, which derived from a preliminary survey and the results of thermographic studies (see the contribution The Preliminary Thermo-Hygrometric Research and Environmental Monitoring of the Sala delle Asse in this volume), which revealed a few structural cracks. It will be possible to review or integrate the arrangement of the transducers based on the results of the above-described survey
The earthquake occurred on the 6th of April 2009 in the Abruzzo Region of Italy seriously hit the... more The earthquake occurred on the 6th of April 2009 in the Abruzzo Region of Italy seriously hit the Cultural Heritage (C.H.) patrimony with major destructive effects on l’Aquila, a city of 70,000 inhabitants with the size and the historical and strategic importance of the capital of the Region. The emergency activities to protect the C.H. have been developed following two parallel levels: (i) damage survey and (ii) design and implementation of temporary safety measures. The organization of emergency actions was managed by a centralized structure, the so-called Function 15 “Protection of Cultural Heritage” directed by a Special Commissioner. The structure coordinated the on-site surveys of protected buildings and the design and implementation of temporary safety measures. Several Italian Universities during and after these first emergency actions were invited by the Commissioner to work on selected Case Histories: the aim was on the one hand to provide a first interpretation of the observed damages and on the other hand to define some guidelines for a higher level of investigation
2012 14th International Conference on Ground Penetrating Radar (GPR), Jun 1, 2012
ABSTRACT Early detection of fractures and internal defects can help quarry owners in cutting quar... more ABSTRACT Early detection of fractures and internal defects can help quarry owners in cutting quarrying costs and reducing the amount of waste products. Valuable stones used in construction industry such as marble, porphyry, granite, travertine, are usually extracted from quarries by cutting blocks whose size normally varies between 5 and 15 m3. Transportation of these blocks from quarries, often located at high altitudes in mountainous environments, down to the headquarters of the stone industry where big machines are installed to transform the big size blocks into slabs or small size stones, can be quite expensive. Money could be saved by checking on-site the big size blocks with NDT methods able to detect internal fractures and other defects (voids, clay inclusions, etc.). A detailed map of fracture extension and orientation can be also very profitable in optimizing the production line. For example, the final destination of a block (i.e., production of slabs rather than small size blocks or other) and the orientation of the cutting planes can be more properly assigned. Currently, Ground Penetrating Radar is the most promising method for this type of application. It can be applied on-site, it can generate high resolution 3D reconstructions of fractures and defects, quasi-real-time results are feasible. Thus, it can be a cost-effective tool, worth being introduced into the quarry industry. To evaluate the potential of this technology for the quarry industry we have been testing the method on marble and porphyry blocks from a couple of quarries belonging to the Brescia stone district (North Italy). Results are very encouraging: all type of defects and fractures that might have an impact on the production line can be detected by 3D surveying the block with a 2GHz GPR system. A dual-polarized antenna is a plus that makes acquisitions faster and easier. Data processing must include two-dimensional filtering to cancel the artifacts generated by side reflections and 3D- migration to generate accurate reconstructions of the target geometries.
3rd Asia Pacific Meeting on Near Surface Geoscience & Engineering, 2020
We discuss the potential of Ground Penetrating Radar (GPR) for tree root mapping by presenting th... more We discuss the potential of Ground Penetrating Radar (GPR) for tree root mapping by presenting the results from three recent studies performed in different sites with secular trees. Depending on the survey area, we discuss the use of two different hardware solutions to perform high density 3D surveys: a single antenna (500MHz or 1GHz) in combination with a PSG (Pad System for Georadar) or a 600MHz array system (IDS Stream C). The results show that GPR method can be an effective tool to map the roots. The approximate extent of the soil volume hosting most of the roots can be easily interpreted after applying a standard data processing sequence. However, advanced image interpretation remains an open issue and, in case a detailed root net reconstruction is needed, the cost of the interpretation phase prevails over the costs of acquisitions and data processing and can significantly affect the overall project costs. Algorithms for automatic root drawing would be the solution but the reliability of such root maps is still to be validated
In 2011, the engineer Giuseppe Albano studied the geometry and state of conservation of the struc... more In 2011, the engineer Giuseppe Albano studied the geometry and state of conservation of the structures of the vault system of the Sala delle Asse to assess any damage and instabilities in the room and proposed a series of studies and monitoring for the cracks that had been detected on the extrados of the lower vault and on the vertical structures, with the aim of identifying any movement that might be un\uadder way. Currently, a diagnostic campaign is in progress, targeted towards understanding the build\uad ing technique and structural behaviour of the vault system. Radar studies were conducted to reconstruct the stratigraphy of the system comprising the lunetted cloister vault, the depressed arch cloister vault above and the floor of the room on the upper floor. Other radar studies were conducted to characterize the raised wall structures, which are of notable thickness (even as much as aver 2.5 m) and to identify cavities and a flue that runs along the full height of the north-east wall. A topographical/diagnostic laser scanner survey will make it possible to reveal the critical points of the structures and types of instability and provide understanding of the dynamics of the crack pattern. The stratigraphic reading will make it possible to codify the archaeological sequence of the built structure, the deterioration and state of damage (the contribution The Diagnostic Survey: The Sala delle Asse and its Context in the present volume).The need to speed Up the time spent collecting information that would be useful for safeguarding and protecting the room forced the immediate installation of a system far monitoring cracks based on the information available at the time, which derived from a preliminary survey and the results of thermographic studies (see the contribution The Preliminary Thermo-Hygrometric Research and Environmental Monitoring of the Sala delle Asse in this volume), which revealed a few structural cracks. It will be possible to review or integrate the arrangement of the transducers based on the results of the above-described survey
Proceedings of the 15th International Conference on Ground Penetrating Radar, 2014
The 19th century restoration works of the Basilica of Sant'Andrea in Mantua consisted of impo... more The 19th century restoration works of the Basilica of Sant'Andrea in Mantua consisted of important modifications of pronaos and facade. According to historical documents, the use of metal reinforcements was planned to tie the facade with the counter-facade but designs and details are missing and since no external evidences of the tie-rods can be observed, the existence of these reinforcements was a fundamental open issue. The problem has been recently addressed with a GPR survey. Some tie-rods have been confirmed. The location of some of them has been problematic because of plaster decorations that reduced the survey area to narrow corridors. The dual-polarization was a benefit because some reinforcements, oriented parallel to the survey corridor, were detected only by the parallel-broadside polarization. In addition, for the exact location of these elements, 3D migration was needed because the reflection was generated out-of-plane. Some other unexpected reinforcements were also detected within the counter-facade wall. The complex geometry of these reinforcements was finally understood by composing the results of GPR investigations on orthogonal faces of the counter-facade. However, a tricky question arose on one side of the wall where an unexpected anomaly in GPR response seemed to reveal the presence of an additional set of metal bars. Again the dual-polarization was essential to exclude this misinterpretation and to understand the real origin of these unexpected signals.
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Papers by Stefano Munda