Lateral Stiffness Discontinuity Effects in Seismic Response of Single-Room RC Buildings

Single-room reinforced concrete (RC) Italian buildings belonging to the second half of 20-th century present similar characteristics, among which the two-level partition of façades, displaying masonry infills placed in contact with the frame structure on the lower level, and glazed ribbon windows on the upper level. This special architectural layout causes a considerable seismic vulnerability, prompting to develop careful performance assessment analyses of this stock of edifices. The study presented in this paper, framed within this research line, is focused on a representative single-room building, used as school gym. The assessment study in current state is carried out via non-linear dynamic analysis, by modelling infills by means of equivalent diagonal struts, and RC members by plastic hinges. The response of the ribbon windows, not expressly simulated in the analysis, is checked in terms of relevant inter-level drift. The results show a significant inelastic response of the infill panels and the RC columns, and very high drifts on the glazed level, resulting in full collapse conditions of the ribbon windows, under a Basic Design Earthquake (BDE)-scaled seismic action.