Evaluation of rack connection mechanical properties by means of the Component Method

Steel storage pallet racks are characterised by the extensive use of thin-walled cold-formed steel members and boltless beam-column connections, whose structural behavior plays a key role in the seismic response of rack systems. Due to the great variety of connector types and member geometries, the current design codes require experimental tests on rack connections to obtain their mechanical characteristics. The drawback is that these experimental procedures are expensive and time-consuming. In this paper a theoretical mechanical model, based on the application of the Component Method (CM), is proposed with the aim to assess the flexural resistance and initial elastic stiffness of rack connections. Results are compared with experimental data collected in an experimental campaign carried out on several full-scale joints, belonging to different types produced by the same manufacturing company. The comparison highlights the accuracy of the proposed model that permits the weakest component of the joint and its failure mode to be evaluated. The CM provides fundamental information about the influence of structural details on the joint behavior, and it could be used in the design of rack connections to improve their structural response. The proposed mechanical model appears appropriate for predicting features of studied connections and especially for analyzing main components, which influence the initial rotational stiffness and the ultimate bending moment of rack connections. Finally the proposed model can be easily modified to be used in the analysis of other connector types, as only a limited number of structural and geometrical data are required for its definition.