Seismic Fragility Models for Unbraced Steel Pallet Racks

Recent Italian earthquakes revealed the significant seismic vulnerability of industrial pallet racks designed for gravity loads only. Nevertheless, these structures remain the most common industrial storage system. Therefore, this study aims to determine the seismic fragility of such structural systems, facilitating more accurate enterprise risk assessments and the development of effective retrofit strategies. To this end, 3D non-linear models of 27 unbraced pallet racks, representative of those used in Italy, were subjected to Time-History analysis under 268 bidirectional seismic events, representative of the Italian seismicity. Multiple fragility models were then developed using various engineering demand parameters and seismic intensity measures through a cloud-based approach.