Comparing cyclic behaviour of RBS, DFC and proposed rigid connections in a steel moment frame with CFT column

ABSTRACT Beam-to-column connection is one of the main parts of steel structures that its failure induces local and/or overall structural failure. This paper aims at examining the impact of different rigid connections (including conventional, reduced beam section (RBS), drilled flange connection (DFC), those stiffened with exchangeable box components and variable-diameter DFC with concrete-filled box columns on the flexural behavior of a steel moment frames. A rhombic connection with a cutting vector pattern like RBS is designed and proposed; then its behavior is compared to those of RBS and DFC connections. The connections are modeled in Abaqus software and then their moment-rotation diagrams are plotted and compared. The results reveal that the DFC connection with holes of different diameters has proper energy absorption and performance. In conclusion, the rhombus DFC connection has a more reliable performance than other DFC connections. In this research, by placing the proposed stiffening components in the connection, it is observed that these components act as dampers increasing the bearing capacity and improve the connection behavior by absorbing the imposed energy. The results indicate that the proposed connection prevents from beam failure as most of input energy is absorbed by the proposed components.