An experimental investigation on solid and perforated steel storage racks uprights

Thin-walled cold-formed (TWCF) profiles are extensively used in adjustable selective pallet racks that represent the most common typology between the logistic solutions. In these structures, vertical members (uprights) are usually channels, often provided with intermediate stiffeners, rear flanges and additional lips. Furthermore, in order to allow for a rapid connection with beams and bracing components, usually uprights present regular perforation systems along their length. Nowadays, theoretical approaches available to design TWCF members are based on equations valid only for few unperforated (solid) cross-section geometries. As a consequence, rack manufacturing engineers frequently adopt the well-known design-assisted-by-testing approach to overcome this limitation and to assess accurately member performance. This approach, time consuming and cost demanding, stresses the need of further improvements required to cover aspects currently not considered in design codes. The paper summarizes the results of a study focused on the response of a commercial upright profile. In particular, 48 compression and 24 bending tests on perforated and unperforated profiles have been carried out. A summary of the experimental program is proposed together with the re-elaboration of test data. Furthermore, the influence of perforation is discussed as well as key design geometric parameters. Finally, owing to the lack of information in major rack standard codes, three different proposals to evaluate the effective second moments of area have been developed, discussed and applied, hoping to contribute to standard improvements.