چكيده لاتين
Due to the importance of technical and economic issues that require double attention in the design and implementation of civil structures today, cold-formed structures are a very suitable option for more use in the construction industry and all structural uses due to the many advantages they have. The light weight of these sheets and their connections is a significant advantage compared to concrete and hot-rolled steel structures. This low weight has a significant effect in reducing the earthquake force on the structure. In addition to this, the lower weight of the materials itself has reduced the construction cost, and due to the ability to recycle these materials, it has doubled their economic efficiency. Among the other advantages of these materials, we can mention the ease and high speed of implementation, which has made the use of cold-rolled sheets to be considered as an ideal option for projects that have time constraints.
Connections in these structures are also very important like other materials. In fact, the connections transfer the forces entering the structure to each other and finally to the foundation and make the structure stable. Beam-to-column connection in these structures is implemented by different sections at different distances. One of these sections, which is widely used in the joints of cold-rolled structures, is the cold-rolled corner section. Various types of screws and rivets are used to connect different sections, among which automatic screws are used more due to their ease of use, high speed of execution and good efficiency. But due to the fact that nuts are not used for these screws, when they are under tension, the connection may break, bend, and crush.
In this research, firstly, the laboratory study of the connection of cold-formed right-angle legs to cold-rolled studs and the effect of various factors on it, such as the thickness of the sheet, the number of connection holes, the size of self-tapping screws, and the effect of washers on the connection. In this research, more than thirty laboratory samples were examined. Laboratory samples were tested in real dimensions and the results were obtained in short intervals. Then, in order to carry out additional studies, numerical samples were modeled using Abaqus software, and after validation with laboratory samples, they were discussed and investigated. Finally, by examining the existing relationships in the regulations of America, Europe and Code 612 and the results obtained from laboratory and numerical studies, an attempt has been made to correct the existing relationships for the buckling and crushing failure modes.
