Non linear modelling of Fornasini tower after the 2012 Emilia earthquake (Italy)

After the seismic sequence that hit the Emilia Region on May 2012, serious damage has been observed in historical fortresses, churches, bell towers and towers, that are particularly common in the area. This has been highlighted by some distinctive features of such seismic motion that revealed to be very critical for structures characterized by long periods, that is: a high spectral displacement demand at long periods and a very high vertical component. Within this context, the paper deals with the interpretation and numerical simulation of the seismic response of Fornasini Tower, that suffered serious damage after such earthquake. To simulate and interpret its seismic response, nonlinear numerical simulations are performed by using in an integrate way various modelling approaches, in particular: the Finite Element (FE) and Equivalent Frame (EF) Models. Both the global seismic response and that of cross vaults at the ground floor have been investigated through the use of nonlinear analyses. In particular, the capability of the EF approach to simulate the global response of the tower is investigated by performing both nonlinear static and dynamic analyses and by using results coming from the more detailed FE approaches to calibrate the parameters in elastic phase. To this aim, the comparison with the real damage occurred is essential to verify the reliability of results achieved.