Structural Behavior of Screwed Connections in Cold-Formed Steel Beams

Two test series were carried out on angle cleat connections between cold-formed channels as beams and rectangular hollow sections as support members. The objective of the tests was to determine the effect of connection rotation from the beam on the shear capacity of the connection. Self-drilling screws were used to attach the channels to the angle cleats with the failure limit states always occurring in this part of the connection. A dual actuator test apparatus that could apply controlled displacement and rotation to the beams was used. The specimens contained different thicknesses of the channels, which allowed for two limit states involving failure modes of the screws fracturing in shear and bearing as well as tilting failure of the screws in the channel sheet material. The experimental results show the effect of rotation on reducing the shear capacity of the screwed connections. An analytical model for the connection is developed using the relation between the bearing force and deformation of the individual screw connections. (C) 2020 American Society of Civil Engineers.