Experimental study of the screw connection of cold-formed steel applied in the same and opposite directions

Abstract

Cold-formed steel has been used widely on buildings, especially for the roof truss-structures. This material and its typical section are beneficial in weight and strength. Despite the minimum total weight, the structure can fulfil the strength requirement. For the truss installations, screws are commonly used to join the truss members due to time consideration and convenience process. However, there is a potential failure using the screw because it does not have a nut to prevent it from detaching. In this research, experimental tests of the screw connection of the cold-formed steel were conducted. The specimens consist of two groups: 8 specimens using screws were applied in the same direction and the other 8 specimens in the opposite direction. A different application of screws was aimed to observe the effect of the screw's head, which may play a role as a nut to prevent detaching. Typical conditions of tilted screw and indented hole on the joined channel section were found during the test. The experimental results showed that the ultimate load for two different directions of screw were slightly different within the range of 0.4 - 10.0 %. The effect of the screw's head position was minor to the resistance of the connection.