Experiments and Shear Strength Predictions of Partially Stiffened and Unstiffened Cold-Formed Channels

Abstract

This paper describes and presents the results of an experimental program on cold-formed steel channel sections to determine the shear strengths of webs with partial transverse stiffening. A total of eighteen tests were conducted using a newly developed dual-actuator test rig at the University of Sydney. The test specimens included two types of cross-sections and various bolting configurations at the two ends of the shear spans. Initially, the background to the AISI S100 shear design rules is reviewed. Subsequently, all test results, including those from this study and test data from the literature, are utilized to calibrate new direct strength method equations to predict the shear strengths of flexural members with partially transversely stiffened webs or without transverse web stiffeners. These rules have been recently incorporated into Supplement 3 of the AISI S100 Specification, Section G2.1 - Flexural Members Without Transverse Web Stiffeners. The paper also includes reliability analyses based on all available test data to provide support for the revision and to determine the resistance factors to be used in the design process. Additionally, a new form of direct strength method equations for shear recently proposed by Glauz is reviewed. Its reliability matches that of the equations recently implemented in Supplement 3, and its simplicity promises a cleaner appearance for the direct strength method design for shear.