Seismic investigation on the Cathedral of Syracuse by finite elements and by a specific rigid body and spring model

The seismic behaviour of the cathedral of Syracuse, Sicily, is investigated by means of two complementary numerical analyses. The monument was built during the 5th century BC, as the Athena temple of Syracuse, and afterward repeatedly modified, mainly by Byzantines and next by Normans, to adapt it to the Christian worship. The complex geometry and the damaged conditions of some masonry elements make the modelling of this monument a challenging task. Moreover, the seismic investigation of this building needs non-linear dynamical analyses that can be practically performed only by adopting models with a limited number of degrees of freedom. Thus, we combined a 3-D finite element linear elastic analysis of the whole building with a 2-D non-linear full dynamical analysis of the transverse section of the building which adopted a specific rigid body and spring model, RBSM. Then, making reference to this latter model, the seismic performance of the building was investigated with reference to a real ground motion recording and to artificial accelerograms whose intensity is compatible with the seismic events that corresponds to return periods of 140 and 475 years.