# Seismic Isolation Devices for Protecting RC Buildings: The Frangipane School in Reggio Calabria
## 1 Introduction  
Seismic isolation represents a well-known efficient technique that can be used to protect buildings and their contents and occupants in case of seismic hazard [1, 2, 3]. Typical examples can find application in newly designed buildings, structures and bridges, where design details can be specified and optimized without restrictions [4, 5]. At the same time, seismic isolation devices are particularly efficient for the retrofit and mitigation of existing buildings and structures that are not able to offer appropriate capacity towards seismic demand, including historic assemblies or even art objects and manufacts [6, 7, 8].  
In this regard, literature efforts include a multitude of research and design contributions where different types of devices or even different modelling techniques are taken into account for optimal seismic retrofit [9], also in terms of hybrid interventions [10].  
Regarding the specific application of seismic devices to existing structures, successful theoretical and practical applications in the Italian context can, in fact, be found, for example, in the form of comparative assessment of rubber-based or friction-based isolation systems for a given structure [9]; multi-criteria optimization process for protection of school buildings [11]; protection intervention for various historical buildings [12], and many other successful international examples [13, 14, 15, 16].  
In the last decades, due to critical safety reasons in the field of structural design, as well as due to continuous technological progress, an increasing number of applications and efforts have been dedicated to seismic isolation aspects [17]. In [18], a review of the historical development of friction-based seismic isolation systems is presented. In this regard, it is important to remind that base isolation cannot be universally applied to structures. In fact, the technique is not suitable for structures resting on soft soils [19], as well as for high-risebuildings [20], and supplementary or even alternative energy dissipation systems should be hence preferred [21; 22; 23].  
In the present paper, a case-study application is presented for the retrofit of an existing school in Reggio Calabria (Italy), and major outcomes of research applications combined with in-field works are summarized. Figure 1, in this regard, shows the location of the examined building and gives clear evidence of a high seismicity level for the Calabria Region.  
Among others, sliding friction bearings are used to mitigate the existing structural members and their content from severe seismic hazards. The present case-study application may look, representative of a typical retrofit intervention, like many others in Italy and worldwide. Besides, it has a particular meaning when the context and the type of building are taken into account. As also summarized in Figure 2, the Reggio Calabria urban context and Region has a long history of severe earthquakes (Figure 2a), which reported collapse and major damage in buildings with thousands of victims (Figure 2b).  
Figure 1: Building context: (**a**) Italian seismicity and (**b**) location of the case-study system.  
Figure 2: Summary of (**a**) seismic intensity and (**b**) the number of victims of past earthquakes in the Calabria Region.  
The existing design standards for seismic resistant buildings on one side, and the availability of a multitude of techniques and computational tools for the vulnerability analysis and mitigation of existing buildings on the other side, are giving evidence of special attention from Municipality Administrations and private companies for the intervention on existing constructed facilities. This is especially the case of so-called \"strategic\" buildings and infrastructural systems, like hospitals, airports, and--among others--schools.