doi:10.3850/978-981-08-5118-7_072

ABSTRACT

The dynamic monitoring of heritage structures subject to environmental dynamic actions is typically the only way for assessing their vulnerability and for updating the available finite element models. It has the advantages, both, of being relatively inexpensive, and of allowing the excitation of large and heavy structures, such as monumental buildings. Nonetheless, serious questions exist about the computational tools for elaborating the sensors data, especially when noisy signals and a limited amount of monitored degrees-of-freedom have to be analyzed. Unfortunately, they are not the only difficulties envisaged. In fact, the level of excitation induced by frequent environmental dynamic loads (such as traffic and moderate winds) is very low, so that the robustness against the noise should be as high as possible in order to enhance the performances of the sensors network and to allow a reliable signal processing. In view of these criticalities, sensors network design strategies may be analyzed to estimate the strength of the acquired signals. Within this framework, the comparison between five optimum criteria has been performed with reference to the Flavian Amphitheater, known worldwide as “Colosseum”. Initially, a brief discussion about the investigated optimum criteria is proposed. Subsequently, a short presentation about the adopted finite element model of the monument is given. Finally, several sensors configurations are carried out by adopting, both, mechanic and energetic optimum design criteria. In the aim to evaluate how the network topologies withstand the presence of disturbs, a performance index based on the Fisher information matrix determinant is estimated by varying the number of sensors to be installed. The best network topology (in terms of robustness against the noise) based on seven measurement points is illustrated.

Keywords: Colosseum, Fisher information matrix, Optimal sensors placement.

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