ABSTRACT
The progressive evolution of the modal damping is used as a key indicator to characterise damage on the building. Modal damping is connected to the mass and the stiffness of structure. Cracking and damage in a structure leads to modification of the vibration modes and consequently of the frequency content of the response records. A full-scale two-storey UnReinforced Stone Masonry (URSM) building is tested on a shaking table in Eucentre, Pavia to investigate the nonlinear behaviour and the failure mechanism of existing URSM structures. The frequency characteristics of the building under subsequent oscillations with gradually increasing intensity vary substantially as it experiences heavy damage over almost the entire NL domain up to collapse. Damage in structures has a significant effect on stiffness but not on mass. The stiffness coefficient i related directly to the stiffness of the structure can be a very sensitive indicator of the damage induced in the structure.
