CORNER DISPLACEMENT RESPONSE SPECTRA FOR ONE-STOREY ECCENTRIC STRUCTURES

The non-linear response of in-plan asymmetric systems has been exten-sively studied since the 1980s. Nevertheless, most of the research effort has been devoted to the study of specific asymmetric buildings and, even though relevant progresses have been achieved in the understanding of the complex translational-to-torsional coupled response of such systems, a full knowledge of the seismic be-havior of planar asymmetric buildings is still not satisfactory. To provide results of more general validity, the authors developed a wide parametric study to obtain trends of the main response parameters such as maximum displacement and rota-tions developed by linear and non-linear one-storey asymmetric structures under earthquake ground motion. Based on a key-parameter of the system (the so-called “alpha” parameter, identified in previous research works by the authors) and on the results of the parametric study, a simplified method for the evaluation of the maximum corner side displacement response of one storey planar asymmetric sys-tem has been proposed by the authors leading to semi-analytical predictions of peak corner displacements expressed through 3D magnification surfaces. In this paper, a real industrial building, which collapsed during the 2012 Emilia Earth-quake due to a strong torsional response caused by the presence of a stiff eccentric wall, is analysed. Different building models are developed including the bare frame structure and the structure with the perimeter stiff wall plus other fictitious structural configurations obtained changing the position of the wall