Effect of Curling Phenomenon on Block Shear and Tear‐out Strengths of Bolted Connections

Block shear and tear‐out behaviours and strengths of cold‐formed steel bolted connections have been thoroughly investigated in the literature. Nevertheless, the curling phenomenon occurring in the thin plate which may affect the strength and behaviour of these failure modes in bolted connections between thin and thick plates has not been researched in detail. Therefore, the behaviour and block shear and tear‐out strengths of bolted connections undergoing the curling effect were investigated through a series of 48 tests at the University of Sydney. Various types of cold‐formed steel sheets (i.e., G300, G450, G500 and G550 to AS 1397) were used for the specimens to obtain a wide range of material properties. The cold‐formed steel sheets with thickness of 1.0 mm, 1.2 mm and 1.9 mm in conjunction with different edge distances as the main variables were studied to investigate the curling effect. On the basis of the experimental results, the observed curling phenomenon not only changed the behaviour but also affected the ultimate strength of the bolted connections. Comparison of the test results with the design specifications and standards from AISI S100:16 (R2020) w/S3‐22 and AS/NZS 4600:2018 demonstrate that the design equations overestimate the nominal shear strength without the consideration of curling. Consequently, a new design equation for the block shear and tear‐out strength considering the curling effect is proposed in this paper.