Experimental investigation of cold-formed steel beam-column sub-frames: Pilot study

This paper presents the findings of an experimental investigation on the structural performance of bolted moment connections in cold-formed steel beam-column sub-frames. A total of eight tests with three different connection configurations in both internal and external columns were carried out. Double lipped C-sections back-to-back with hot rolled steel gusset plates of 10 mm and of 16 mm in two different shapes were tested; four bolts per member were used in the connections. Among the tests, three different modes of failure were identified and the measured moment resistances at the connections were found to vary from 36% to 97% of the measured moment capacities of the cold-formed steel sections, demonstrating that bolted moment connections between cold-formed steel members are structurally feasible and economical. Furthermore, structural members with double lipped C sections back-to-back are shown to be practical in constructing short to medium span portal frames with bolted moment connections through rational design.