Uncertainty quantification in structural health monitoring: Applications on cultural heritage buildings (original) (raw)
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Structural health monitoring of historical buildings in Italy
Safety, Reliability, Risk and Life-Cycle Performance of Structures and Infrastructures, 2014
Health assessment of historical buildings by means of monitoring systems is for sure a fundamental step to preserve architectural heritage, especially for countries as Italy, rich in ancient monuments. Events such as earthquakes or severe weather phenomena constitute a major risk for these buildings because of their age and the related weakness to sustain exceptional excitations. The availability of a continuous, real time and automatic structural health monitoring system is considered a useful tool for early detection of a potentially dangerous situation for the structure and its occupants. The A c c e p t e d M a n u s c r i p t choice of the best measurement strategy provided by the monitoring system is crucial: a compromise must be found between the need of information, complexity of the measuring system and the related costs. Due to the difficulty in modelling most historical structures, it is a hard task to fix proper and safe limits relying on model-generated predictions only. The availability of long-term records of the structural response can help get this goal, not just relying on models, but also detecting changes in some parameters obtained from time records. This paper presents a challenging example: the structural health monitoring of the Duomo di Milano main spire during and after restoration.
Automated data analysis for static structural health monitoring of masonry heritage structures
Structural Control and Health Monitoring, 2020
Funding information Ajuntament de Sant Cugat through a project aimed at monitoring the Monastery of Sant Cugat, ref. num. C-10764. Ministry of Education, Culture and Sports of the Spanish Government through a project aimed at studying the structural condition of Mallorca Cathedral, ref. num. 2/131400106ca-5/030300592 EF. AGAUR agency of the Generalitat de Catalunya and European Social Fund, through a predoctoral grant awarded to the corresponding author. Ministry of Science, Innovation and Universities of the Spanish Government and European Regional Development Fund through the SEVERUS project, ref. num. RTI2018-099589-B-100. Summary Masonry heritage structures are often affected by slow irreversible deterioration mechanisms that can jeopardise structural stability in the foreseeable future. Static structural health monitoring (SHM), aimed at the continuous measurement of key slow-varying parameters, has the potential to identify such mechanisms at a very early stage. This can greatly facilitate the implementation of adequate preventive and remedial measures which can be critical to ensure that such structures are preserved for generations to come. However, since monitored parameters usually experience reversible seasonal variations of the same order of magnitude as changes caused by active mechanisms, identification of the latter is often a difficult task. This paper presents a fully integrated automated data analysis procedure for complete static SHM systems utilising dynamic linear regression models to filter out the effects caused by environmental variations. The method does not only produce estimated evolution rates but also classifies monitored responses in pre-defined evolution states. The procedure has successfully been used to identify vulnerable areas in two important medieval heritage structures in Spain, namely the cathedral of Mallorca and the church of the monastery of Sant Cugat.
Sensors and Smart Structures Technologies for Civil, Mechanical, and Aerospace Systems 2020, 2020
Static structural health monitoring (SHM), aimed at the continuous measurement of slow-varying parameters over a long period, has been proved to be a powerful tool to support the diagnosis of masonry heritage structures. In such applications, the initial interpretation task involves the identification of evolutionary conditions from recorded data. However, this can be difficult since monitored features are influenced by environmental changes. In addition, many masonry heritage structures are characterised by a complex structural behaviour stemming from the interaction among different elements, making the task of interpreting SHM data for diagnosis very challenging. One such structure is the church of the monastery of Sant Cugat close to Barcelona, built mostly between the 12th and 15th centuries. Certain key structural parameters of the church have been monitored since 2017 with the aim of understanding the cause of visible pathologies and identifying any active deterioration mechanisms that could pose a threat to the structural integrity of the church in the future. This paper presents the application of an automated data analysis methodology to this problem. The method uses dynamic regression models to filter out components related to reversible seasonal fluctuations from measurements and automatically classifies monitored parameters into evolutionary states based on predicted evolution rates and dispersion metrics from the filtering procedure. A tool is presented which allows analysis results to be updated as new data is received. Finally, results from the proposed methodology are used for the diagnosis of the structure and their usefulness in a broader decision-making framework is discussed.
Structural Health Monitoring of Historical Buildings: Preventive and Post-Earthquake Controls
Structural health monitoring (SHM) has been recently more and more utilized in the study of Cultural Heritage (CH) buildings, as a key activity to increase the knowledge on their structural behavior and to have a deeper insight into their conditions. This knowledge allows engineers to carry out with more confidence and only if necessary a strengthening intervention, and it helps to prevent the execution of intrusive repair works, if not justified by an experimentally demonstrated worsening of the structural conditions. The use of monitoring systems applied under ordinary conditions and installed on CH structures may allow to: (i) validate the functioning of the adopted structural models; (ii) identify the ongoing damaging processes; (iii) validate the effectiveness of the strengthening interventions.
Long-term monitoring for the condition-based structural maintenance of the Milan Cathedral
Construction and Building Materials, 2019
The Milan Cathedral, whose main structures were erected between 1386 and 1813, is one of the largest masonry monuments ever built. Within the traditional collaboration between Politecnico di Milano and Veneranda Fabbrica del Duomo di Milano the historic Institution established in 1387 and responsible for the preservation and development of the Cathedral a structural monitoring system was recently designed and implemented with the twofold objective of assisting the condition-based structural maintenance of the Cathedral and creating a large archive of experimental data, useful to improve the knowledge of the monument. The new monitoring system, fully computer based and with efficient transmission of the collected data, includes static and dynamic measurements. The static monitoring system consists of: (a) bi-axial tilt-meters installed at the top of selected piers and at 3 levels of the Main Spire; (b) vibrating wire extensometers mounted on the iron tie-rods which are characterized by the higher tensile stress; (c) temperature and humidity sensors for the measurement of internal and external environmental parameters. The dynamic monitoring is performed through seismometers (electro-dynamic velocity sensors) installed at the top of 14 selected piers and at 3 levels of the Main Spire. After a concise historic background on the Milan Cathedral and the description of the sensing devices installed in the church, the paper focuses on the results obtained during the first months of monitoring (since October 16th, 2018) and the lessons learned in view of the Structural Health Monitoring (SHM) of the monument.
Structural Health Monitoring for cultural heritage constructions: a resilience perspective
IABSE Symposium, Guimarães 2019: Towards a Resilient Built Environment Risk and Asset Management, 2019
Disturbances or disruptive events may induce reductions of functionality of the built environment. For Cultural Heritage (CH) structures, functionalities may range from technical, to economic ones linked to touristic activities, up to intangible functionalities related to the cultural and social value of these constructions. Resilience can be defined as the capability of a system overcome a disturbance with the minimum total loss of functionality over time. Structural Health Monitoring (SHM) may enhance resilience by providing information that can support decision making, aiming to reduce the impact of the disturbances. In this paper, the benefits of SHM systems as means for improving resilience of CH structures are addressed and discussed with specific reference to the three different decision situations; before, during and after events of disturbances. Examples of real applications of SHM for CH structures and its effect on the resilience of the system conclude the paper.
Structural monitoring for the evaluation of the dynamic response of historical monuments
2008
The paper illustrates the application of the structural monitoring for the evaluation of the dynamic behaviour of two monuments, the stone tomb of Cansignorio della Scala in Verona, Italy, and the Qutb Minar in Delhi, India. Both systems have been conceived to acquire ambient vibrations, to evaluate the dynamic response of the monuments, and for the recording of seismic events. The control of the dynamic behaviour is related to the local environmental conditions. In addition, a limited number of displacement transducers are placed across the most significant cracks of the monuments, to evaluate the possible damage evolution. The stone tomb of Cansignorio della Scala is part of a monumental funerary complex in gothic style located in the centre of Verona. The Qutb minar, 72.5 m tall, located in the city centre of New Delhi, is particularly sensitive to wind actions, therefore an anemometer was placed on the top of the tower. The evaluation of the results of the monitoring will permit...
Journal of Cultural Heritage
The paper discusses the monitoring-based approach unfolded to evaluate the health condition of a heritage structure in Portugal. An extensive experimental campaign, including geometric survey, visual inspections, damage diagnosis, monitoring and control, is carried out to support and evaluate the actions undertaken to re-establish the structural strength. The paper focuses on the analysis of case-specific static and dynamic parameters deemed representative of the structural behaviour and highlights the benefits associated with the implementation of a monitoring-weighed methodology in terms of diagnostics of the system's vulnerabilities as well as control of the effectiveness of the adopted consolidation measures. The results demonstrate the feasibility and suitability of this systematic experimental approach for the noninvasive assessment of the structural fitness of built cultural heritage.
Optimized procedures and strategies for the dynamic monitoring of historical structures
Journal of Civil Structural Health Monitoring, 2016
Compared with other diagnostic techniques, which are limited to the local investigation, the structural dynamic monitoring allows to obtain information about seismic response and vulnerability of structures, in their whole. The experimental modal analysis evaluates the dynamic parameters such as frequencies, vibration modes and damping coefficients. For historic buildings, due to their heterogeneity and complexity, these data are not yet readily available. The possibility of applying the simplified procedures for the dynamic identification of the different historic structural typologies is, therefore, strategic to obtain useful information to apply the design criteria and the structural verifications in the seismic field. Besides the simplified procedures allow an optimization both on the execution time and on the costs. The paper provides some hypothesis of simplified dynamic monitoring procedures through the reduction/optimization of the accelerometric sensors used for three case studies, which differ in structural typology such as Churches, Towers and Palaces.