Experimental and numerical assessment of isolation seismic device for retrofit of industrial existing RC sheds

Prefabricated industrial sheds featured a high seismic vulnerability during the 2012 Emilia earthquake (Italy). The buildings typically exhibited a rigid collapse mechanism that was a consequence of the lack of connection between columns, beams and roof elements. The study presents an experimental and numerical assessment of a novel isolation device which has been designed to improve the seismic performance of industrial sheds. The device, which is placed on the top of the column, exploits the movement of a rigid body on a sloped surface to provide horizontal stiffness and control the lateral displacement of the beam. Biaxial tests are performed to investigate the effect of the vertical load, the velocity of sliding and the number of cycles on the force – displacement response of the device. To cope with the capacity of the testing equipment, the experimental campaign is carried out on a scaled model of the device, and the protocol is designed accounting for similarity requirements. The backbone curve of the tested prototype is eventually derived from the experimental data. In the second part of the study, a 3D finite element model of the prototype is formulated in Abaqus and used to switch the backbone curve from the scaled model to the full-scale device. A parametric study is conducted to evaluate the influence of the inclination of the sloped surface and the coefficient of friction on the output force of the system.