Modelling and analysis of an Italian Medieval Castle under earthquake loading: diagnosis and strengthening

In this paper the Italian Medieval Castle of San Niccolò (Toscana, Italy) is analysed in order to assess its structural behaviour and its seismic vulnerability with respect to the actual state of conservation. A quasi-static approach for the evaluation of the seismic loads has been used (as indeed common in many analyses of the seismic behaviour of masonry structures). The comparison demand vs. capacity confirms the susceptibility of this type of buildings to extensive damage and possibly to collapse, as frequently observed. Herein, starting from a single case study, a contribution to the issue of modelling and analysis of monumental masonry buildings under seismic action is provided. The effects of the current techniques for repairing and strengthening are then investigated in order to evaluate the effectiveness of the usual retrofitting techniques.