Experimental and Numerical Investigation of a Dissipative Connection for the Seismic Retrofit of Precast RC Industrial Sheds

Abstract

Past earthquakes have highlighted the seismic vulnerability of prefabricated industrial sheds typical of past Italian building practices. Such buildings typically exhibited rigid collapse mechanisms due to the absence of rigid links between columns, beams, and roof elements. This study aims at presenting the experimental and numerical assessment of a novel dissipative connection system (DCS) designed to improve the seismic performance of prefabricated sheds. The device, which is placed on the top of columns, exploits the movement of a rigid slider on a sloped surface to dissipate seismic energy and control the lateral displacement of the beam, and to provide a recentering effect at the end of the earthquake. The backbone curve of the DCS, and the effect of vertical load, sliding velocity, and number of cycles were assessed in experimental tests conducted on a scaled prototype, according to a test protocol designed accounting for similarity requirements. In the second part of the study, non-linear dynamic analyses were performed on a finite element model of a portal frame implementing, at beam-column joints, either the DCS or a pure friction connection. The results highlighted the effectiveness of the DCS in controlling beam-to-column displacements, reducing shear forces on the top of columns, and limiting residual displacements that can accrue during ground motion sequences.