Browsing by Author "Pecorelli, Marica Leonarda"

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    Comparison of semi-active control strategies for rocking objects under pulse and harmonic excitations
    (Elsevier, 2016-12-28) Ceravolo, Rosario; Pecorelli, Marica Leonarda; Zanotti Fragonara, Luca
    Recently, a considerable literature has grown up around the theme of seismic protection of rigid blocks, with a special focus on strategies to reduce the overturning vulnerability due to rocking motion. The present paper investigates a semi-active control method for rocking blocks and compares different strategies for its implementation. In more detail, a feedback control algorithm was developed to adjust the stiffness of the restraints placed at the two lower corners of the block. The utility of the proposed control was quantified through “ad hoc” indices derived from overturning spectra. The performance of a feedback strategy was numerically investigated and specific simulations were performed to quantify the control method degradation when implemented for a real-world application. Finally, the stability of the block controlled with the proposed strategy is compared with the stability of the block whose anchorage is set according to different control strategies.
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    Dynamic investigation on the Mirandola bell tower in post-earthquake scenarios
    (Springer , 2016-07-19) Zanotti Fragonara, Luca; Boscato, Giosue; Ceravolo, Rosario; Lentile, Silvia; Russo, Salvatore; Pecorelli, Marica Leonarda; Quattrone, Antonino
    After the seismic events of the 20th and 29th of May 2012 in Emilia (Italy), most of the monumental and historic buildings of the area were severely damaged. In a few structures, partial collapse mechanisms were observed (e.g. façade tilting, out-of-plane overturning of panels…). This paper presents the case-study of the bell tower of the Santa Maria Maggiore cathedral, located in Mirandola (Italy). The dynamic response of the structure was evaluated through operational modal analysis using ambient vibrations, a consolidated non-destructive procedure that estimates the dynamic parameters of the bell-tower. The dynamic tests were carried out in pre-intervention and post-intervention conditions in order to understand the sensitivity of dynamic measurements to safety interventions. Furthermore, a comparative study is made with similar cases of undamaged masonry towers up to the 6th mode. Finally, an investigation on the state of connections and of the building itself is carried out via FE model updating.
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    A multi‐objective genetic algorithm strategy for robust optimal sensor placement
    (Wiley, 2021-02-17) Civera, Marco; Pecorelli, Marica Leonarda; Ceravolo, Rosario; Surace, Cecilia; Fragonara, Luca Zanotti
    The performance of a monitoring system for civil buildings and infrastructures or mechanical systems depends mainly on the position of the deployed sensors. At the current state, this arrangement is chosen through optimal sensor placement (OSP) techniques that consider only the initial conditions of the structure. The effects of the potential damage are usually completely neglected during its design. Consequently, this sensor pattern is not guaranteed to remain optimal during the whole lifetime of the structure, especially for complex masonry buildings in high seismic hazard zones. In this paper, a novel approach based on multi‐objective optimization (MO) and genetic algorithms (GAs) is proposed for a damage scenario driven OSP strategy. The aim is to improve the robustness of the sensor configuration for damage detection after a potentially catastrophic event. The performance of this strategy is tested on the case study of the bell tower of the Santa Maria and San Giovenale Cathedral in Fossano (Italy) and compared to other classic OSP strategies and a standard GA approach with a single objective function.