Experimental validation of plastic ovalization strategy for seismic-resistant Automated Rack Supported Warehouses

With the aim of proposing possible solutions for seismic-resistant Automated Rack Supported Warehouses (ARSWs), this paper studies the possibility of considering plastic ovalization of the diagonal-to-upright bolted connection to increase the global seismic performance. In the transversal direction of the structure, so-called cross-aisle direction, diagonals are connected to the upright through a single bolt, and the leading failure mechanism of the connection is plastic ovalization, due to the low thickness of the diagonal element. The bearing resistance is usually far lower than the resistance of the element. Given the difficulties of increasing the bearing resistance without also increasing the resistance of the element, the idea is to exploit the ductility associated to the plastic ovalization and to design all the other members of the upright frame to be over-resistant with respect to that. The actual behaviour of the diagonal-upright system is validated through the execution of an experimental campaign where tensile and compression monotonic tests are performed, as well as cyclic ones, both on short and full-length elements. Various configurations of the connections are tested to see how the geometric parameters (i.e., dimension of the holes for the connection and their position) affect the resistance of the connection and the behavior of the diagonal.