Experimental Investigations on Overlapped Purlins Under Gravity and Uplift Loadings

Abstract Thin‐walled cold‐formed steel structures represent a competitive solution for a wide range of structural applications due to their efficient use of material and rapid manufacturing and installation. For purlin systems continuous Z‐shaped steel purlins with overlapping over the intermediate supports are the best choice to minimize material use. Based on the outcomes of an extensive numerical investigations done by the authors an experimental campaign was designed and performed. The testing outcomes are to be used to confirm the reliability of numerical models and the identification of a simple analytical model. The experimental setup consists of a simply supported beam incorporating the overlapped connection which is being loaded at mid‐span by a point load. The setup aims to reproduce the loading condition of the support of a continuous beam. The overlapped purlins were tested under gravity and uplift loading. To capture as much as possible the real behavior of the purlin, the sheeting was included in the setup. One cross‐section was tested for various symmetric overlaps: 100 mm, 300 mm, 450 mm, 600 mm, 900 mm and 1200 mm. The design of lapped purlins was found to be primarily influenced by the length of the span and the overlap length. The current paper presents the outcomes of the experimental campaign and compares the results with a simplified analytical model. The analytical model was shown to provide a safe estimate of the capacity of the connection.