Seismic Protection of Adjustable Pallet Racking Structures with Isolation Systems

The importance of storage facilities along the supply chain is something that is becoming vital toa sector that has seen a skyrocketing increase in demand during the past decade. Yet, designingreliable and functional racking systems does still pose a great challenge to the engineers due tothe lack of specifications that clearly address their extremely fragile mechanisms for resistingseismic-induced lateral forces. The aim of this work is to portray a clear picture of theperformance of selective pallet racking systems in the presence of lateral actions, often inducedby ground shaking. This research proposes two new strategies for the retrofit of non-compliantpallet racking, moving in the panorama of the current hardware know-how, but at the same timepushing the limits of sensible solutions based on consolidated principles. The results ofexperimental shaking table tests performed using real-time earthquake records are used toinvestigate the suitability of tailor-made devices to create isolation systems for standard palletracks. A curved-surface sliding (CSS) bearing is considered for the physical tests, which had beenengineered and preliminarily tested by FIP Industriale (Padua, Italy) under the patented nameIsolGOODS. The tests were carried out in the FIP Laboratory. A first investigative study hasconsidered the system response under six ground motions and has allowed drawing first anduseful conclusions on the practical effectiveness of the novel device. Numerical modelingtechniques have given clear indications on when and where CSSs can provide the best economic-to-performance ratio. A novel concept, based on well-recognized seismic principles, wastherefore conceived with the aim of providing a middle-range solution for improving theperformance of pallet-racking systems along the cross-aisle direction. The proposed base-plateconnection, designed for promoting upright uplift when the lateral forces exceed a certainthreshold, was tested in the NTUA Laboratory of Steel Structures (Athens, Greece) usingmonotonic and cyclic protocols. A more comprehensive picture of the behavior of upright frameswhen equipped with the proposed device is formed as the result of numerical investigation. [edited by Author]