Group effects of multiple self-drilling screws on the connection shear strength for high strength cold-formed steel

Abstract

High Strength cold-formed steel has been widely used in the construction of the low and medium-rise buildings nowadays. Self-drilling screws are an economical fastener to join the cold-formed thin-gauge steel together. Research has been carried out to understand the behaviour of multiple self-drilling screws connection for high strength cold-formed steel. This paper presents a study to investigate the behaviour and strength of self-drilling screw connections for high strength cold-formed steel. A total of 12 single shear screwed connection specimens with different number of screws were tested. The experimental results were compared with calculated analytical results using North American Specification (NAS) of the American Iron and Steel Institute (AISI) and Australian Standards (AS 4600) equations. Various failure modes were observed during the testing, including tilting, bearing and combination of tilting and bearing and shearing of screws. The findings show that the influence of the “Group Effect” is minimal in the screw connection with high strength cold-formed steel.