European alternatives to design perforated thin-walled cold-formed beam–columns for steel storage systems

• Uprights are a key component of steel storage pallet racks, made from cold-formed thin walled members.
• The presence of regular perforation systems in the uprights is considered in a simplify way for rack design
• European upright design can be developed according to three design alternatives, leading to different performances.
• Column/beam-column verification is sometimes unsafe, being load carrying capacity greater than the elastic buckling load.

SummaryRack systems to store goods and products are one of the most important applications for thin-walled cold-formed steel members. Adjustable pallet racks are used widely worldwide and are characterized by regular systems of perforations along the uprights (i.e. vertical members) to connect easily pallet beams and diagonal members forming the skeleton frame. Design rules are based on the well-established approaches for the more traditional solid members, suitably extended to account for the presence of regular perforations via component tests accurately described in rack specifications.This paper focuses on the performance of isolated uprights under axial load and gradient moment. In particular, three European alternatives to design beam–column rack members have been discussed and applied: the first and the second are traditionally used for thin-walled cold-formed steel members while the latter, the so-called general method of Eurocode 3 part 1-1, allows to take directly into account the key features associated with upright response. The geometry of the cross-sections and of their perforation system, the member slenderness and the load condition has been assumed as parameters of this study. Research outcomes demonstrate that the predicted performances can result significantly different, reflecting directly on the weight and the cost of the whole storage system. Furthermore, numerical analyses and design calculations show that standard codes need urgent revisions, leading in few cases to design beam–columns from the unsafe side.