The use of simplified multi-story models in characterizing damage potential of earthquake ground motions

The characterization of effective damage potential of the earthquakes implies the identification of structural response parameters which reliably represent the most significant features in development of damage in the real structures. For this purpose, models that adequately describe the seismic response of structures must be adopted. As widely recognized, some significant parameters characterizing the cyclic histories of the seismic response can be selected to represent the damaging process of the structures. Obviously, the effects of structural damage reflect also on damaging non-structural elements and technical devices. The seismic response of multi-story structural systems subjected to severe ground motions should be studied at both global and local levels, as it could be characterized by high demands for inelastic displacement and energy dissipation, often causing concentration of damage in limited zones of the structure. These local effects depend on the type of signal and on the structural characteristics and cannot be predicted by means of SDOF systems. In this research simplified procedures have been adopted for the investigation on the seismic response of multi-story frame structures: inelastic equivalent SDOF systems for the global response of the frame and inelastic equivalent shear-type model for the prediction of local seismic demand in terms of displacements and energy. The results have been also used in estimating the damage imparted to the structures by means of available damage models.