The study presents the results of model experimental investigations and nonlinear numerical analyses of thin-walled, two-segment box structures with various configurations of integral corrugated stiffeners. The models for experimental testing were fabricated using additive manufacturing techniques. Five variants of the structure were examined, including a reference configuration without reinforcement. The experimental investigation was carried out using a dedicated test rig. Numerical representations of the investigated models were developed and subjected to nonlinear analyses using finite element method (FEM)-based software. The adequacy of the numerical results was assessed through comparison with experimental data. The objective of the study was to determine the effect of different forms of the proposed structural solution on the magnitude of the critical load and the nature of post-buckling deformation.