The research activity developed in the present work achieved both technical and scientific results on the seismic risk assessment of masonry towers. It provided semi empirical formulations for the main frequency estimation based on a wide database of historic masonry towers and a novel framework for the seismic risk assessment starting from the Bayesian model updating using dynamic experimental data. The recent Italian earthquakes have dramatically highlighted the vulnerability of historic masonry constructions and the need to improve the knowledge on their seismic response. Due to this fact, the challenging issue of obtaining a reliable structural model has become increasingly relevant to the scientific community, promoting the employment of sophisticated tools of analysis and the need of numerical models to be set up. However, the significant lack of knowledge on historical structures (e.g., material properties, geometry, construction techniques, boundary conditions), still makes their numerical modelling difficult. The knowledge of the seismic response of this structural typology, taking into account uncertain parameters, represents a critical issue and the main scientific question to which this work aimed to answer. The framework proposed in this research started with the Finite Element (FE) model updating of masonry towers through Bayesian approach; the prior distribution of relevant uncertain model parameters was converted into the posterior one by using experimental dynamic data. Nonlinear static analyses were employed to estimate the uncertainties in the seismic response of masonry towers. Taking into account both the modelling and the measurement uncertainties, fragility curves were defined related to different towers damage levels. Eventually, the seismic hazard was considered thus leading to the seismic risk assessment of masonry towers. The idea of this work started from the necessity of obtaining a better awareness of the uncertainties involved in the seismic capacity prediction of historic constructions, and their effect on the overall reliability. Although the proposed results are based on the application to a real case study, the procedure may be used for other similar structures and may represent an effective and alternative tool for the seismic risk quantification of historic masonry constructions.

On the role of uncertainties in the seismic risk assessment of historic masonry towers / Silvia Monchetti. - (2018).

On the role of uncertainties in the seismic risk assessment of historic masonry towers

Silvia Monchetti
2018

Abstract

The research activity developed in the present work achieved both technical and scientific results on the seismic risk assessment of masonry towers. It provided semi empirical formulations for the main frequency estimation based on a wide database of historic masonry towers and a novel framework for the seismic risk assessment starting from the Bayesian model updating using dynamic experimental data. The recent Italian earthquakes have dramatically highlighted the vulnerability of historic masonry constructions and the need to improve the knowledge on their seismic response. Due to this fact, the challenging issue of obtaining a reliable structural model has become increasingly relevant to the scientific community, promoting the employment of sophisticated tools of analysis and the need of numerical models to be set up. However, the significant lack of knowledge on historical structures (e.g., material properties, geometry, construction techniques, boundary conditions), still makes their numerical modelling difficult. The knowledge of the seismic response of this structural typology, taking into account uncertain parameters, represents a critical issue and the main scientific question to which this work aimed to answer. The framework proposed in this research started with the Finite Element (FE) model updating of masonry towers through Bayesian approach; the prior distribution of relevant uncertain model parameters was converted into the posterior one by using experimental dynamic data. Nonlinear static analyses were employed to estimate the uncertainties in the seismic response of masonry towers. Taking into account both the modelling and the measurement uncertainties, fragility curves were defined related to different towers damage levels. Eventually, the seismic hazard was considered thus leading to the seismic risk assessment of masonry towers. The idea of this work started from the necessity of obtaining a better awareness of the uncertainties involved in the seismic capacity prediction of historic constructions, and their effect on the overall reliability. Although the proposed results are based on the application to a real case study, the procedure may be used for other similar structures and may represent an effective and alternative tool for the seismic risk quantification of historic masonry constructions.
2018
Gianni Bartoli, Klaus Thiele
ITALIA
Silvia Monchetti
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Utilizza questo identificatore per citare o creare un link a questa risorsa: https://hdl.handle.net/2158/1130895
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