Stub-Column Tests on Pallet Racks Uprights with and Without Reinforcements

This paper presents an experimental and numerical investigation into the axial compression behaviour of cold-formed steel uprights used in adjustable pallet rack systems. The study focuses on the influence of locally applied reinforcements on the load-bearing capacity, post-peak response, and failure mode of perforated upright sections. The experimental campaign comprised 400-mm-long specimens, including three nominally identical unreinforced uprights and three reinforced uprights characterized by different reinforcement layouts. Monotonic stub-column tests were performed in accordance with the design-assisted-by-testing provisions of EN 15512:2020 + A1:2022. The experimental response was assessed in terms of load–displacement behaviour, maximum resistance, post-peak degradation, and observed deformation patterns. The results show a consistent response among the unreinforced specimens and indicate that the reinforcement arrangement affects the post-peak behaviour and residual load-carrying capacity more markedly than the initial stiffness and peak resistance. A geometrically and materially nonlinear finite element model was subsequently developed in ABAQUS. The model explicitly included the upright perforations, elastic–plastic material behaviour, and initial geometric imperfections derived from linear buckling modes. A dynamic implicit solution procedure was adopted to reproduce the complete experimental response. The numerical results show good agreement with the experimental curves in terms of initial stiffness, maximum load, post-peak trend, and deformation pattern. The proposed experimental and numerical framework provides component-level data and modelling tools for subsequent robustness and progressive-collapse assessments of pallet rack systems.