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System identification and structural health monitoring of bridge structures
Full text linkThis research study addresses two issues for the identification of structural characteristics of civil infrastructure systems. The first one is related to the problem of dynamic system identification, by means of experimental and operational modal analysis, applied to a large variety of bridge structures. Based on time and frequency domain techniques and mainly with output-only acceleration, velocity or strain data, modal parameters have been estimated for suspension bridges, masonry arch bridges, concrete arch and continuous bridges, reticular and box girder steel bridges. After giving an in-depth overview of standard and advanced stochastic methods, differences of the existing approaches in their performances are highlighted during system identification on the different kinds of civil infrastructures. The evaluation of their performance is accompanied by easy and hard determinable cases, which gave good results only after performing advanced clustering analysis. Eventually, real-time vibration-based structural health monitoring algorithms are presented during their performance in structural damage detection by statistical models.
The second issue is the noise-free estimation of high order displacements taking place on suspension bridges. Once provided a comprehensive treatment of displacement and acceleration data fusion for dynamic systems by defining the Kalman filter algorithm, the combination of these two kinds of measurements is achieved, improving the deformations observed. Thus, an exhaustive analysis of smoothed displacement data on a suspension bridge is presented. The successful tests were subsequently used to define the non-collocated sensor monitoring problem with the application on simplified model
Structural assessment outcomes from the demolition of an arch bridge with cluster modal analysis
Full text linkAn old arch bridge was subject to demolition due to life-cycle damage and environmental issues, in a central-east region of Italy. During the demolition process, several dynamic tests were executed in order to evaluate the structural behavior before and during demolition. The classical Modal Analysis methods revealed difficulty in determining the modal parameters, so these results were validated with a newly developed technique of modal parameter identification and then verified with sophisticated finite element models. The structure revealed some surprising results relatively to the dynamic
characteristics before and after the partial demolition
Structural health monitoring of historical buildings in Italy: applications and uncertainty overview
Full text linkStructural Health Monitoring (SHM) is currently more and more considered (and applied) in It- aly for 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 on their actual conditions, reducing uncertainties connected to material properties and structural capacity. In recent years the research group at the University of Padua, in collaboration with public administrations, has installed several SHM systems on heritage structures: two case studies are presented and discussed within this paper. The Arena of Verona and the Cathedral of Conegliano are excellent examples of ongoing monitoring activities, performed through static and dynamic approaches. In parallel to the application of innovative monitoring techniques, statistical models and data processing proce- dures have been developed and applied in order to eliminate uncertainties and exploit monitoring results for an effective assessment and protection of historical constructions
Uncertainty quantification in structural health monitoring: applications on cultural heritage buildings
Full text linkIn the last decades the need for an effective seismic protection and vulnerability reduction of cultural heritage buildings and sites determined a growing interest in structural health monitoring (SHM) as a knowledge-based assessment tool to quantify and reduce uncertainties regarding their structural performance. Monitoring can be successfully implemented in some cases as an alternative to interventions or to control the medium- and long-term effectiveness of already applied strengthening solutions. The research group at the University of Padua, in collaboration with public administrations, has recently installed several SHM systems on heritage structures. The paper reports the application of monitoring strategies implemented to avoid (or at least minimize) the execution of strengthening interventions/repairs and control the response as long as a clear worsening or damaging process is detected. Two emblematic case studies are presented and discussed: the Roman Amphitheatre (Arena) of Verona and the Conegliano Cathedral. Both are excellent examples of on-going monitoring activities, performed through static and dynamic approaches in combination with automated procedures to extract mean- ingful structural features from collected data. In parallel to the application of innovative monitoring techniques, statistical models and data processing algorithms have been developed and applied in order to reduce uncertainties and exploit monitoring results for an effective assessment and protection of historical constructions. Processing software for SHM was implemented to perform the continuous real time treatment of static data and the identification of modal parameters based on the structural response to ambient vibrations. Statistical models were also developed to filter out the environmental effects and thermal cycles from the extracted features
Chapter 28. Dynamic testing and structural identification of ""New People's Bridge"" in Verona
No full textReliability analysis and in-field investigation of a r.c. bridge over river Adige in Verona, Italy
No full textIn this paper will be presented an assessment procedure done on an existing historical r.c. bridge in Verona.
A reliability analysis has been performed with a f.e. model considering stochastic data about materials. An in- situ survey has been done to collect data about materials, geometry and damage. Finally, a modal analysis has been carried out to identify the bridge structural system and assess damage. Information about material damage, serviceability and safety has been retrieved
Sviluppo e applicazioe di algoritmi per l'identificazione dinamica e il rilevamento del danno delle strutture civili
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Dynamic system identification of bridges: development of automatic algorithms in the frequency domain for continuous monitoring
No full textLa tesi è incentrata sulla realizzazione di un algoritmo automatico capace di fornire i modi di vibrare di strutture esistenti (ponti nel caso in esame ma è estendibile pure ad edifici) partendo dagli output forniti dal metodo FDD (Frequency Domain Decomposition). Si è così in grado di monitorare l'andamento delle frequenze medie dei modi individuati nel tempoope
Ponti integrali: analisi statica e sismica
Full text linkIn questo elaborato si è inizialmente studiata la diffusione dei ponti integrali nel mondo, riassumendone vantaggi e problematiche. Viene riservato ampio spazio allo studio dei particolari costruttivi e ai limiti geoemtrici suggeriti nei vari paesi. Successivamente, utilizzando i dati relativi a tre ponti progettati con una soluzione Semi Integrale si sono svolte delle analisi parametriche al fine di capire quale sia il comportamento di questo tipo di ponti al variare di alcuni parametri significativi. Le analisi parametriche svolte sono sia di tipo statico che di tipo sismico e a tal proposito, viene effettuato un confronto tra le sollecitazioni negli elementi principali del ponte dovute ai carichi statici e quelle dovute al sisma, cercando di capire le principali differenze rispetto ai ponti tradizionali. Infine si è svolto un confronto tra la tipologia Semi Integrale e la tipologia Completamente Integrale andando a indagare i vantaggi relativi all'uso di entrambe le soluzioniope
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