Seismic performance of ductile connections between precast beams and roof elements

The seismic vulnerability of precast reinforced concrete buildings is often governed by the performance of mechanical connections between precast elements. This aspect was highlighted by recent seismic events in Italy, where several collapses were registered among industrial buildings typical of Italian practice. The building damage was related to failure of connections between beams and columns and between beams and roof elements, which led to the loss of support of the structural elements. Starting from the results of an experimental campaign, the present work investigates the use of ductile connections between precast beams and roof elements suitable for both new structures and as a retrofit measure of existing ones. These connections are able to transfer the horizontal inertial loads and to accommodate deformations arising from seismic displacement compatibility. The relative rotation between the end of the roof elements and the beam, owing to seismic displacement demand, could lead to their contact. This leads to a load increase in rigid connections, which can cause their premature failure, or to horizontal relative displacements as in the ductile connections considered herein. Moreover, the connections investigated could be used to dissipate seismic energy.