Behavior and Design of Block Shear Strength of Beam-End Bolted Connections Using Cold-Formed Steel Channels

The block shear strengths of simple cold-formed steel bolted connections for members in tension have been thoroughly investigated, whereas the combined effects of shear rotation on the strengths of beam-end bolted connections failing in block shear have not been studied in detail. In this paper, an experimental program on full-scale shear beam-end bolted connections is presented, where the cold-formed steel (CFS) channels are bolted to mild steel T-shaped sections, which are then rigidly connected to a rectangular hot-rolled steel (RHS) column. A dual-actuator setup comprising two actuators was used in the test apparatus to investigate the effect of the combined shear force and beam-end rotation on the block shear behavior and shear strength of the connections. A total of 78 tests were carried out at the University of Sydney, with 200 mm depth CFS channels of thicknesses of 1.2 mm and 1.5 mm, in conjunction with various shear distances between the bolts as the main variable to evaluate the effect of the shear fracture paths and fracture process behavior on the shear strength rupture of the connections. Consequently, the test results are compared to the current cold-formed steel design procedures from AS/NZS 4600 and AISI S100 to verify whether the existing design equations and methodologies are accurate for determining the shear capacity of the full-scale shear beam-end bolted connections under the combined effects of shear rotation and fracture. A reliability analysis of the design equations is also included in the paper.