ABSTRACT
Analysis and safety assessment of masonry structures under seismic loads are still a controversial issue, due to both the well known difficulties in defining the non-linear mechanical properties of materials, and the selection of suitable models and procedures. In this regard, the recently issued Italian seismic code OPCM/3431 (2005) requires that the collapse acceleration for the whole construction be calculated even for strengthening intervention, at least for determining the priorities. On the other hand, when local intervention do not substantially modify the original behaviour, the Italian Guidelines on the evaluation and reduction of cultural heritage seismic risk (Linee Guida, 2006) suggest to carry out the safety assessment through simplified procedures, since complete analysis of the whole structure might be excessively complex from a computational point of view, or scarcely representative due to insufficient modelling.
