ABSTRACT
In the last decade, structural identification techniques through dynamic in situ tests have been widely used to investigate the global dynamic behavior of ordinary buildings and built cultural heritage. The choice of proper boundary conditions at the base of the structure, however, is still a critical point in the development of sound numerical models able to reproduce building dynamic response reliably. The contribution of the foundation soil should be ascertained and, if necessary, properly modelled. The paper tries to shed light on the issue of soil-structure-interaction on the structural identification of masonry towers, with reference to the case study of the bell tower of Santa Sofia Church in Benevento (Italy). The experimental results of the dynamic identification, i.e. frequencies and modal shapes, have been interpreted and employed to calibrate both simplified and advanced numerical models of the soil-foundation-tower system. In the first case, soil compliance is represented by a set of springs attached at the base of the tower, which has been modelled as a 1D system. In the second case, a 3D finite element model comprehensive of the tower, the soil and the foundation structure has been developed. Pros and cons of the two numerical approaches on the structural identification process are highlighted and discussed.
