Seismic performance of irregular 3D RC frames

his paper deals with seismic performance of an irregular mass-eccentric 3D RC framed structure subjected to seismic actions. The sample structure has three double-span and six-storey plane frames and it is stiffness-regular both in plan and in elevation. A very detailed model has been set through the computer code Zeus, which takes into account all the main characteristics of inelastic behaviour of rc structures. The seismic input has been defined by considering seven ground motions reproducing the design specrum provided by EC8 and scaled in order to impose different values of PGA. Seismic response of the structure has been analyzed by performing a nonlinear dynamic analysis. In the analyses, mass center has been shifted from stiffness center at a distance going from zero to 15% of the relevant building plan dimension. Seismic responses, expressed in terms of top displacement and interstorey drift, have been evaluated for each selected value of PGA and eccentricity.