| Summary: | Cold-formed steel (CFS) structures are becoming popular due to their lightweight, high strength, and sustainability. However, CFS structures are susceptible to connection failures, which can be a major safety concern. Self-drilling screws are a common type of fastener used in CFS connections, but their tensile performance is not well understood. This is particularly true for web connections, which are subjected to tensile forces in service. This paper presents the results of laboratory work on the tensile performance of CFS C-Section back-to-back (BTB) web connections made with self-drilling screws. The effects of CFS thickness and screw numbers on the ultimate tensile load, Pu, and failure modes of the BTB web connections were investigated. Mechanical properties of tensile stress were determined based on the testing procedure from ASTM E8. The tested materials were 75 mm × 75 mm size of CFS C-Section plates with 0.75 mm and 1.00 mm of thicknesses and the M5.5 carbon steel self-drilling Hex screw with 4-inch length. A total of 12 specimens of BTB web connection samples were tested under tension, with two main testing parameters which were the thicknesses (0.75 mm and 1.0 mm) and the number of connected screws (2 and 4 units). From the results of the tensile tests, the average yield tensile stress for CFS C-Section plate and M5.5 screw exceeds 500 N/mm2. Meanwhile, the performance of BTB web connection shows that Pu had increased with addition number of screws (nos) and/or thicker thickness of the CFS C-Section plate. Based on the laboratory results, adding more nos and thicker plate resulted in a minimum of 57% Pu improvement and a maximum of 164%. The main mode of failures was identified due to the bearing deficiency. Fewer screws snapped in the testing. It is noting that the design with sufficient plate thickness with appropriate nos may optimize the design with higher tensile load of the BTB web connection and avoid the bearing or shearing failures. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024.
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