Novel Aluminium Alloy Exoskeleton for Seismic Upgrading of a Typical Historical Masonry Clustered Building in Southern Italy

Most of unreinforced masonry buildings stand in aggregate configuration, representing a huge percentage of Italian existing construction stocks. These edifices were built in continuity one to each other during the slow expansions occurred in the past centuries. Since they were conceived to resist only gravity loads and due to their actual advanced state of decay, they are very vulnerable to earthquakes. For these reasons, their seismic vulnerability assessment and the consequential retrofitting interventions are a pressing need, which represents a challenging issue in the engineering field both for the lack of detailed information about their constitutive structural units and the complexity of the numerical modelling approaches. In this paper, the seismic appraisement of a typical historical clustered masonry building placed in Southern Italy is discussed. Firstly, a short introduction regarding the historical, geometrical and structural features of the case study is carried out. Once collected these data, static non—linear analyses are performed to obtain capacity curves. Based on the achieved results, an innovative aluminium alloy coating system, consisting of metal exoskeletons integrated with thermo—insulating panels, is proposed for the seismic upgrading of the aggregate. Subsequently, pushover analyses on the strengthened FE model of the clustered building are carried out, highlighting the effectiveness of this innovative retrofitting technique. Finally, the study is concluded by plotting the mechanical—based fragility curves for each structural units, before and after the intervention, so to observe the reduction of the observed damage level produced by the used integrated coating system.