Joint-Ph.D. at the Department of Civil and Environmental Engineering, University of Perugia, Italy and the Department of Civil Engineering, University of Minho, Portugal. Alban does research on dam engineering, earthquake engineering, Structural Health Monitoring, FE numerical modeling Supervisors: Prof. Filippo Ubertini; Prof. Paulo B. Lourenço
Abstract The paper presents an overview of the results of diagnostic and monitoring activities ca... more Abstract The paper presents an overview of the results of diagnostic and monitoring activities carried out in the last years through satellite radar interferometry (2011–2016) and in situ measurements (2017–2019) in the historical city of Gubbio, Italy. The study is aimed at contributing to understanding the potential of remote sensing technologies in measuring complex deformation phenomena in historic buildings, such as those caused by soil-structural interaction and earthquakes, considering the monumental Consoli Palace and the Town Walls as case studies. The research activities have been carried out within the European HERACLES project, funded in the framework of Horizon (2020) and aimed at proposing novel diagnostic monitoring solutions for enhancing heritage resilience against various types of hazards. Particular attention is focused on the cross-correlation of the outputs of satellite radar interferometry and in-situ structural monitoring data aimed at achieving engineering meaningful results supporting decision making and proactive interventions.
Abstract Resilience of new and existing buildings to climate change is a key research issue. Clim... more Abstract Resilience of new and existing buildings to climate change is a key research issue. Climate change-related phenomena can considerably affect buildings mechanical and thermal-energy response by contributing to materials degradation and structural safety. Such an impact is even further exacerbated in historical constructions, more vulnerable to such events due to their ancient structure if compared to recent designs. The purpose of this paper is to propose an innovative, integrated, multidisciplinary methodology for assessing construction materials’ degradation in historic masonry buildings and its potential future evolution, providing a risk mapping accounting for interactions between climate change effects and structural damage. Such a replicable approach consists in (i) preliminary site inspections, (ii) damage and degradation surveys, (iii) development and calibration of numerical models predicting structural-thermal response and (iv) prediction of materials degradation accounting for future climate conditions and potential worsening of structural damage. The final output of the procedure is a hierarchical mapping of regions with different degradation severities, by identifying those where a specific type of degradation or damage insists but are likely stable and those where they are expected to get worse due to changes in future climate conditions or to a negative interaction between degradation and damage. The presented approach is applied to an iconic Italian monumental building, the Consoli Palace in Gubbio, where future climate scenarios up to 2080 are simulated according to the IPCC climate change predictions. Results highlight that thermal-energy and structural aspects need to be jointly considered in the preservation of surface materials of historic buildings exposed to climate change severity.
Abstract This paper presents a methodology aimed at addressing the rapid post-earthquake damage l... more Abstract This paper presents a methodology aimed at addressing the rapid post-earthquake damage localization and quantification tasks in heritage masonry structures, based on non-linear Incremental Dynamic Analysis (IDA). The proposed methodology relies on pre-run multidimensional non-linear IDA simulations carried out using a numerical Finite Element model together with vibration data recorded during an earthquake. The IDA curves are built with reference to different portions of the structure, relating meaningful local damage parameters to relevant seismic intensity measures. The selection of appropriate intensity parameters is crucial and a study on this aspect is carried out. The methodology is validated through application to a numerical model of a reduced-scale masonry structure, called Brick House, which is a well-known international benchmark tested on the LNEC-3D shaking table. The obtained results demonstrate that, if the set of IDA curves has been previously constructed using a suitable model, the proposed methodology yields an immediate and accurate estimation of damage conditions after an earthquake is recorded.
This paper presents a novel method for rapidly addressing the earthquake-induced damage identific... more This paper presents a novel method for rapidly addressing the earthquake-induced damage identification task in historic masonry towers. The proposed method, termed DORI, combines operational modal analysis (OMA), FE modeling, rapid surrogate modeling (SM) and non-linear Incremental dynamic analysis (IDA). While OMA-based Structural Health Monitoring methods using statistical pattern recognition are known to allow the detection of small structural damages due to earthquakes, even far-field ones of moderate intensity, the combination of SM and IDA-based methods for damage localization and quantification is here proposed. The monumental bell tower of the Basilica of San Pietro located in Perugia, Italy, is considered for the validation of the method. While being continuously monitored since 2014, the bell tower experienced the main shocks of the 2016 Central Italy seismic sequence and the on-site vibration-based monitoring system detected changes in global dynamic behavior after the ea...
8th International Conference on Computational Methods in Structural Dynamics and Earthquake Engineering Methods in Structural Dynamics and Earthquake Engineering
Conservation techniques within the framework of structural health monitoring, particularly throug... more Conservation techniques within the framework of structural health monitoring, particularly through dynamic measurements and operational modal analysis, are becoming popular for condition-based maintenance and decision-making in historic structures. Nonetheless, while effective for giving insight into the overall behaviour of structures, these techniques may fail at detecting local damages with limited effects on the modal features of the system. In this regard, the analysis of propagating waves throughout the structure poses an attractive alternative for data-driven damage identification. Specifically, some encouraging results have been reported on the application of seismic interferometry to reinforced concrete structures, albeit the number of works concerning ambient vibrations is far scarce, and practically nonexistent in the realm of historic structures. In this light, this article explores the synergistic application of operational modal analysis and ambient noise deconvolution...
The response of the San Pietro monumental bell-tower located in Perugia, Italy, to the 2016 Centr... more The response of the San Pietro monumental bell-tower located in Perugia, Italy, to the 2016 Central Italy seismic sequence is investigated, taking advantage of the availability of field data recorded by a vibration-based SHM system installed in December 2014 to detect earthquake-induced damages. The tower is located about 85 km in the NW direction from the epicenter of the first major shock of the sequence, the Accumoli Mw6.0 earthquake of August 24th, resulting in a small local PGA of about 30 cm/s2, whereby near-field PGA was measured as 915.97 cm/s2 (E–W component) and 445.59 cm/s2 (N–S component). Similar PGA values also characterized the two other major shocks of the sequence (Ussita Mw5.9 and Norcia Mw6.5 earthquakes of October 26th and 30th, respectively). Despite the relatively low intensity of such earthquakes in Perugia, the analysis of long-term monitoring data clearly highlights that small permanent changes in the structural behavior of the bell-tower have occurred after the earthquakes, with decreases in all identified natural frequencies. Such natural frequency decays are fully consistent with what predicted by non-linear finite element simulations and, in particular, with the development of microcracks at the base of the columns of the belfry. Microcracks in these regions, and in the rest of tower, are however hardly distinguishable from pre-existing ones and from the physiological cracking of a masonry structure, what validates the effectiveness of the SHM system in detecting earthquake-induced damage at a stage where this is not yet detectable by visual inspections.
This paper presents a methodology aimed at addressing the rapid post-earthquake damage localizati... more This paper presents a methodology aimed at addressing the rapid post-earthquake damage localization and quantification tasks in heritage masonry structures, based on non-linear Incremental Dynamic Analysis (IDA). The proposed methodology relies on pre-run multidimensional non-linear IDA simulations carried out using a numerical Finite Element model together with vibration data recorded during an earthquake. The IDA curves are built with reference to different portions of the structure, relating meaningful local damage parameters to relevant seismic intensity measures. The selection of appropriate intensity parameters is crucial and a study on this aspect is carried out. The methodology is validated through application to a numerical model of a reduced-scale masonry structure, called Brick House, which is a well-known international benchmark tested on the LNEC-3D shaking table. The obtained results demonstrate that, if the set of IDA curves has been previously constructed using a suitable model, the proposed methodology yields an immediate and accurate estimation of damage conditions after an earthquake is recorded.
This paper presents an enhanced version and the validation of a recently proposed methodology for... more This paper presents an enhanced version and the validation of a recently proposed methodology for earthquake-induced damage detection and localization in masonry towers by using long-term vibration monitoring data. The proposed enhanced method is based on continuous operational modal analysis through stochastic subspace identification, dynamic multiple linear regressive analysis to remove the effects of changing environmental conditions and finite element (FE) model updating. Any anomalous frequency deviation from normal conditions resulting from an earthquake triggers the damage localization process. This task is performed by solving an inverse FE model calibration problem, where equivalent elastic properties of macrostructural elements are identified by minimizing an objective function considering experimentally identified and numerically predicted damage induced decays in natural frequencies and changes in eigenvector components. To minimize the computational effort of this calibration procedure, a quadratic surrogate model is constructed using a tuned numerical FE model of the structure. The methodology is validated through application to the "Sciri Tower", an historic civic masonry tower located in Perugia, Italy, that has been continuously monitored by the authors for more than 1 year. The validation is carried out by using simulated damage scenarios and a set of real far-field earthquake data and is based on a FE model of the tower including surrounding buildings , calibrated on the basis of the measured data from ambient vibration tests. The results demonstrate that the proposed procedure is capable of correctly detecting and localizing earthquake-induced damages.
Abstract The paper presents an overview of the results of diagnostic and monitoring activities ca... more Abstract The paper presents an overview of the results of diagnostic and monitoring activities carried out in the last years through satellite radar interferometry (2011–2016) and in situ measurements (2017–2019) in the historical city of Gubbio, Italy. The study is aimed at contributing to understanding the potential of remote sensing technologies in measuring complex deformation phenomena in historic buildings, such as those caused by soil-structural interaction and earthquakes, considering the monumental Consoli Palace and the Town Walls as case studies. The research activities have been carried out within the European HERACLES project, funded in the framework of Horizon (2020) and aimed at proposing novel diagnostic monitoring solutions for enhancing heritage resilience against various types of hazards. Particular attention is focused on the cross-correlation of the outputs of satellite radar interferometry and in-situ structural monitoring data aimed at achieving engineering meaningful results supporting decision making and proactive interventions.
Abstract Resilience of new and existing buildings to climate change is a key research issue. Clim... more Abstract Resilience of new and existing buildings to climate change is a key research issue. Climate change-related phenomena can considerably affect buildings mechanical and thermal-energy response by contributing to materials degradation and structural safety. Such an impact is even further exacerbated in historical constructions, more vulnerable to such events due to their ancient structure if compared to recent designs. The purpose of this paper is to propose an innovative, integrated, multidisciplinary methodology for assessing construction materials’ degradation in historic masonry buildings and its potential future evolution, providing a risk mapping accounting for interactions between climate change effects and structural damage. Such a replicable approach consists in (i) preliminary site inspections, (ii) damage and degradation surveys, (iii) development and calibration of numerical models predicting structural-thermal response and (iv) prediction of materials degradation accounting for future climate conditions and potential worsening of structural damage. The final output of the procedure is a hierarchical mapping of regions with different degradation severities, by identifying those where a specific type of degradation or damage insists but are likely stable and those where they are expected to get worse due to changes in future climate conditions or to a negative interaction between degradation and damage. The presented approach is applied to an iconic Italian monumental building, the Consoli Palace in Gubbio, where future climate scenarios up to 2080 are simulated according to the IPCC climate change predictions. Results highlight that thermal-energy and structural aspects need to be jointly considered in the preservation of surface materials of historic buildings exposed to climate change severity.
Abstract This paper presents a methodology aimed at addressing the rapid post-earthquake damage l... more Abstract This paper presents a methodology aimed at addressing the rapid post-earthquake damage localization and quantification tasks in heritage masonry structures, based on non-linear Incremental Dynamic Analysis (IDA). The proposed methodology relies on pre-run multidimensional non-linear IDA simulations carried out using a numerical Finite Element model together with vibration data recorded during an earthquake. The IDA curves are built with reference to different portions of the structure, relating meaningful local damage parameters to relevant seismic intensity measures. The selection of appropriate intensity parameters is crucial and a study on this aspect is carried out. The methodology is validated through application to a numerical model of a reduced-scale masonry structure, called Brick House, which is a well-known international benchmark tested on the LNEC-3D shaking table. The obtained results demonstrate that, if the set of IDA curves has been previously constructed using a suitable model, the proposed methodology yields an immediate and accurate estimation of damage conditions after an earthquake is recorded.
This paper presents a novel method for rapidly addressing the earthquake-induced damage identific... more This paper presents a novel method for rapidly addressing the earthquake-induced damage identification task in historic masonry towers. The proposed method, termed DORI, combines operational modal analysis (OMA), FE modeling, rapid surrogate modeling (SM) and non-linear Incremental dynamic analysis (IDA). While OMA-based Structural Health Monitoring methods using statistical pattern recognition are known to allow the detection of small structural damages due to earthquakes, even far-field ones of moderate intensity, the combination of SM and IDA-based methods for damage localization and quantification is here proposed. The monumental bell tower of the Basilica of San Pietro located in Perugia, Italy, is considered for the validation of the method. While being continuously monitored since 2014, the bell tower experienced the main shocks of the 2016 Central Italy seismic sequence and the on-site vibration-based monitoring system detected changes in global dynamic behavior after the ea...
8th International Conference on Computational Methods in Structural Dynamics and Earthquake Engineering Methods in Structural Dynamics and Earthquake Engineering
Conservation techniques within the framework of structural health monitoring, particularly throug... more Conservation techniques within the framework of structural health monitoring, particularly through dynamic measurements and operational modal analysis, are becoming popular for condition-based maintenance and decision-making in historic structures. Nonetheless, while effective for giving insight into the overall behaviour of structures, these techniques may fail at detecting local damages with limited effects on the modal features of the system. In this regard, the analysis of propagating waves throughout the structure poses an attractive alternative for data-driven damage identification. Specifically, some encouraging results have been reported on the application of seismic interferometry to reinforced concrete structures, albeit the number of works concerning ambient vibrations is far scarce, and practically nonexistent in the realm of historic structures. In this light, this article explores the synergistic application of operational modal analysis and ambient noise deconvolution...
The response of the San Pietro monumental bell-tower located in Perugia, Italy, to the 2016 Centr... more The response of the San Pietro monumental bell-tower located in Perugia, Italy, to the 2016 Central Italy seismic sequence is investigated, taking advantage of the availability of field data recorded by a vibration-based SHM system installed in December 2014 to detect earthquake-induced damages. The tower is located about 85 km in the NW direction from the epicenter of the first major shock of the sequence, the Accumoli Mw6.0 earthquake of August 24th, resulting in a small local PGA of about 30 cm/s2, whereby near-field PGA was measured as 915.97 cm/s2 (E–W component) and 445.59 cm/s2 (N–S component). Similar PGA values also characterized the two other major shocks of the sequence (Ussita Mw5.9 and Norcia Mw6.5 earthquakes of October 26th and 30th, respectively). Despite the relatively low intensity of such earthquakes in Perugia, the analysis of long-term monitoring data clearly highlights that small permanent changes in the structural behavior of the bell-tower have occurred after the earthquakes, with decreases in all identified natural frequencies. Such natural frequency decays are fully consistent with what predicted by non-linear finite element simulations and, in particular, with the development of microcracks at the base of the columns of the belfry. Microcracks in these regions, and in the rest of tower, are however hardly distinguishable from pre-existing ones and from the physiological cracking of a masonry structure, what validates the effectiveness of the SHM system in detecting earthquake-induced damage at a stage where this is not yet detectable by visual inspections.
This paper presents a methodology aimed at addressing the rapid post-earthquake damage localizati... more This paper presents a methodology aimed at addressing the rapid post-earthquake damage localization and quantification tasks in heritage masonry structures, based on non-linear Incremental Dynamic Analysis (IDA). The proposed methodology relies on pre-run multidimensional non-linear IDA simulations carried out using a numerical Finite Element model together with vibration data recorded during an earthquake. The IDA curves are built with reference to different portions of the structure, relating meaningful local damage parameters to relevant seismic intensity measures. The selection of appropriate intensity parameters is crucial and a study on this aspect is carried out. The methodology is validated through application to a numerical model of a reduced-scale masonry structure, called Brick House, which is a well-known international benchmark tested on the LNEC-3D shaking table. The obtained results demonstrate that, if the set of IDA curves has been previously constructed using a suitable model, the proposed methodology yields an immediate and accurate estimation of damage conditions after an earthquake is recorded.
This paper presents an enhanced version and the validation of a recently proposed methodology for... more This paper presents an enhanced version and the validation of a recently proposed methodology for earthquake-induced damage detection and localization in masonry towers by using long-term vibration monitoring data. The proposed enhanced method is based on continuous operational modal analysis through stochastic subspace identification, dynamic multiple linear regressive analysis to remove the effects of changing environmental conditions and finite element (FE) model updating. Any anomalous frequency deviation from normal conditions resulting from an earthquake triggers the damage localization process. This task is performed by solving an inverse FE model calibration problem, where equivalent elastic properties of macrostructural elements are identified by minimizing an objective function considering experimentally identified and numerically predicted damage induced decays in natural frequencies and changes in eigenvector components. To minimize the computational effort of this calibration procedure, a quadratic surrogate model is constructed using a tuned numerical FE model of the structure. The methodology is validated through application to the "Sciri Tower", an historic civic masonry tower located in Perugia, Italy, that has been continuously monitored by the authors for more than 1 year. The validation is carried out by using simulated damage scenarios and a set of real far-field earthquake data and is based on a FE model of the tower including surrounding buildings , calibrated on the basis of the measured data from ambient vibration tests. The results demonstrate that the proposed procedure is capable of correctly detecting and localizing earthquake-induced damages.
Uploads
Papers by Alban Kita