07.16: On the distortional buckling capacity of pallet rack uprights

Abstract

ABSTRACTIn nowadays commercial environment, the storage of goods on standardized pallets represent the standard for many companies. As a direct consequence, pallet rack storage systems have become an essential part in their intralogistics. Usual load bearing structures of storage systems consist of longitudinal and transversal frames. In longitudinal direction, along the aisle, the vertical distance between beams is varied function requirements. In transversal direction, usually the frame is a truss structure composed of uprights as chords, diagonals and struts.For the load bearing structure of pallet rack systems, the uprights represent the main elements. Following a long optimization process to increase the load bearing capacity of cold formed elements, the critical load associated with local buckling was increased by introducing folds acting as longitudinal stiffeners. This approach solved local buckling problems but created the premises for another sectional instability, i.e. distortional buckling. The stability issue is further accentuated by arrays of holes along the length of the uprights. These holes enable the user to customize the shelf height, depending on storage requirementsBased on an extensive experimental program developed within the ACTEX laboratory (https://erris.gov.ro/ACTEX), the present paper presents the findings of a numerical study conducted for a heavy load pallet rack upright profile. The aim is the identification of stabilizing stiffness needed to prevent the development of distortional buckling. Based on the numerical results, a series of preliminary solutions are proposed to restrain distortional buckling and improve the cross sectional stability of pallet rack uprights.