In seismic-prone areas, ecclesiastical masonry complexes have shown very high vulnerability, as detected after the last Italian earthquakes, such as those that occurred in L’Aquila (2009), Emilia-Romagna (2012), Central Italy (2016), and Ischia (2017). Partial collapses often affect these types of aggregate buildings due to the presence of highly vulnerable elements, such as bell towers. Preliminary analyses, including straightforward and quick methods, are necessary to assess their vulnerability. This paper proposes a simplified method to analyse bell tower dynamic behaviour and the results obtained are compared with several different approaches. The first is based on the dynamics of two rigid blocks (bell tower and lower building), and the second concerns a single block (bell tower only). The proposed method can be considered as a quick procedure involving few parameters to provide a preliminary analysis before use of more complex models such as finite element models. It aims to provide a valuable tool for the initial evaluation of the stability and risk index of the structure. The double-block model considers the associations between the rocking of the bell tower and the sliding motion of the underlying building. A parametric evaluation for different friction coefficients is proposed. The results are represented as rotation time histories and compared with analysis of the single vulnerable element, i.e., the bell tower subjected to the floor spectrum. The results show that high excitation frequency and friction coefficient values make the bell tower stable, and that the simplified model provides a clear safety advantage.

The development of innovative early warning systems (EWS), structural health monitoring (SHM) and structural health monitoring and reinforcement (SHMR) systems is essential to prevent the occurrence of potentially dangerous events on engineering works, buildings and in the natural environment. Their effectiveness can be improved by using new generation sensors able to realize widespread, low-cost monitoring at increasing spatial and temporal resolution. The main aim of the research is, therefore, to develop a versatile strain transducer capable of monitoring elements of different nature such as slopes, buildings and linear infrastructures performing distributed real-time measurements. The paper introduces a new smart hybrid transducer (NSHT), a strain transducer belonging to the distributed optical fiber sensors family, appositely designed to overcome the drawbacks of traditional solutions. An experimental laboratory setup was arranged to test its reliability and a comparison between measurements retrieved by the NSHT and traditional devices were done. The results showed that the NSHT is able to perform strain monitoring with spatial resolution as high as 5 cm and accuracy comparable to that of the traditional devices. Finally, an integrated structural and geotechnical monitoring system architecture based on its use is proposed for the Petacciato site, where a deep-seated landslide affects the historical town and some infrastructures. To realize a single communication line in such a complex monitoring system, where multiple elements have to be monitored, a specific tool was also designed and tested, that allows the exact spatial identification of the various elements under observation. Although on-site validation is needed, these early results are encouraging and demonstrate that the NSHT is a low-cost transducer with great potential and that, looking forward, it can be used to increase the effectiveness of the existing EW, SHM and SHMR Systems. The development of systems involving NSHT also follows the new approach to innovation policy contributing to different points of the 2030 Agenda

This work describes the application of a new transducer prototype for continuous monitoring in both the structural and geotechnical fields. The transducer is synthetically constituted by a wire of optical fiber embedded between two fiber tapes (fiberglass or carbon fiber) and glued by a matrix of polyester resin. The fiber optical wire ends have been connected to a control unit whose detection system is based on Brillouin optical time-domain frequency analysis. Three laboratory tests were carried out to evaluate the sensor’s reliability and accuracy. In each experiment, the transducer was applied to a sample of inclinometer casing sets in different configurations and with different constraint conditions. The experimental collected data were compared with theoretical models and with data obtained from the use of different measuring instruments to perform validation and calibration of the transducer at the same time. Several diagrams can compare the transducer and highlight its suitability for the monitoring and maintenance of structures. The characteristic of the transducer suggests its use as a mixed system for reinforcing and monitoring, especially in the lifetime maintenance of critical infrastructures such as transportation and service networks, and historical heritage.

The masonry have been studied with idealistic model, for historical masonry of a centuries-old building, it is really difficult to apply the above said simplifications, the intriguing rules deduced from laboratory studies and also the numerical patterns are more and more sophisticated. Below are some considerations made in reference to a specific case study: Palazzo Ducale in Parete, of Caserta province. In this palace, it was quite impossible to imagine a model which could faithfully reflect the masonry history of over a thousand years. Some extremely simplified approaches are able to provide information about the capacity of the structure. Furthermore, results from nonlinear static analyses are presented. Indications on the congruence between codes rules and results from numerical analyses performed according to the Italian seismic code are supplied. The results show that generally imposing the best approach for the generic case could not be satisfying for the particular one.