Ductile connection for the seismic retrofitting of precast buildings

The recent Italian seismic events (2009 L'Aquila and 2012 Emilia), as well as the Turkish ones (1998 Adana, 1999 Kocaeli, 2003 Bingol and 2011 Van), showed the importance of connections design, relevant to avoid partial or total collapses of precast buildings. This topic has been discussed widely in different international meetings and it has been object of several university laboratory tests, all around Europe. The European code EN 1998-1:2005 (paragraph 5.11.2.) introduces requirements and design criteria for connections of precast elements. This research deals with the interaction between existing connections made by steel dowels, and ductile connections made by steel devices, positioned outside of the concrete elements. The aim of this study is to evaluate the seismic forces acting both in the dowels and in the devices presented. The research started with analyzing the mechanical features of existing dowels and their behavior under cyclic and seismic-type loads. Moreover the study kept analyzing the interaction of the new steel devices with structural concrete elements in order to design properly the connection system of the device, relevant for the transmission of the seismic forces. Finally, inelastic non-linear analyses have been carried out to verify the efficiency of the devices applied to different and common types of precast buildings present in the European market, and to verify that the displacements of the building match with the allowable ones of the devices.