Unbraced pallet rack design in accordance with European practice–Part 2: Essential verification checks

• Warping displacements, forces and moments in mono-symmetric cross-section.
• The resistance of the cross-section of the uprights is influenced by the bi-moment.
• Safety index for stability evaluated with the system length approach is unsafe.
• Safety index for stability evaluated with the modified Wood׳s approach is unsafe.
• An adequate approach for the stability safety index evaluation is proposed.

This paper concludes a two-parts paper focusing on the design of steel storage pallet racks in accordance with the European provisions EN 15512 “Steel static storage systems – Adjustable pallet racking systems”. In part 1, “Selection of the Method of Analysis”,a parametric study has been presented on medium-rise semi-continuous unbraced racks differing for components, geometries and degrees of flexural stiffness of both beam-to-column joints and base-plate connections. The choice of the method of analysis has been discussed, stressing out the influence of both the warping effects and the importance of univocal rules for designers to evaluate the elastic critical buckling loads of the overall frame as well as of the uprights (i.e, the vertical components in racks).This second part deals with rack design and considers serviceability lateral displacements of the whole rack and both resistance and stability ultimate limit states for the uprights. The different alternatives associated directly with the requirements of the design provisions. or not in contrast with them, have been discussed and applied in order to single out their differences in terms of safety index as well as in the optimal use of the material. Concluding remarks underline the weak points of the European rack standards and are of practical interest for structural engineers, stressing clearly when the recommended procedures fail, hence leading to an unsafe and uneconomic design.