Structural performance on bolted sleeved connections between two CFS channel sections subjected to combined bending and shear

Abstract

An experimental investigation was carried out to study the behavior of the sleeve connection between two cold-formed steel (CFS) channel sections subjected to combined bending and shear. A total of thirty-nine specimens including three control specimens were tested under three-point bending for different parameters such as three types of the span to section depth ratio, three different sleeve lengths, two sleeve thicknesses and two bolt configurations. Each tested specimen consisted of a pair of channel sections braced together using hot rolled angle sections along the length to ensure lateral stability. The test results indicate two different failure modes; local buckling due to combined bending and shear in the purlin section adjacent to sleeve end, and the other is shearing of the self-drilling screw at the tension zone. The moment resistance of the sleeve connection varied directly with the sleeve length to section depth ratio. The interaction study carried out between the proposed critical sleeve moment and shear capacity of the sleeve specimens is found to be conservative with respect to the AISI interaction equation. The resistance factor for load and resistance factor design (LRFD) method and safety factor for allowable strength design (ASD) method is proposed for the design of sleeve connection by considering it as a flexural member. The design uniformly distributed load (wD) of sleeve specimens having an average sleeve length to section depth ratio of 2.17, 3.51, and 4.85 are found to be 80, 103, and 125% the capacity corresponding to control specimen respectively. The proposed design method is also applicable to the design of continuous channel purlin/girt sections with 150 mm depth for any number of spans subjected to UDL.