Investigation of Cyclic Behavior on Types of Reduced Beam Section Moment Connections in Flange

Nowadays, the use of innovative methods such as cross-sectional reduction method in designing moment connections of steel structures has become widespread among designers. The method of reducing the cross section by deliberately weakening the beam in a part close to the connection of the beam and column reduces the plastic strains of the joint and the formation of a plastic hinge in the beam. In this paper, the effect of reduced beam section (RBS) on joint strength by removing the plastic hinge from the column and also the optimal performance of various reduced beam section shapes through different indicators such as hysteresis curve, pushover diagram, energy dissipation of connection and … are checked. In this research, modelling and nonlinear analysis of 10 examples of reduced beam section with and without beam section reduction using ABAQUS software has been investigated under cyclic loading. The results showed that all models with reduced beam section have the ability to transfer the place of formation of plastic strains or the same plastic hinge into the beam and away from the column. Among all the methods of reducing the cross-section, the method of reducing flange beam section with uneven holes and enlarging inward to the beam has shown a better performance than other samples. The energy dissipation of this method is increased 68% versus the reference sample without reduced section. The flexural capacities of sample with reducing flange beam section with uneven holes and enlarging inward to the beam has shown better cyclic performance. The values of flexural capacity in the mentioned sample is decreased 33% versus the reference sample without reduced section. This subject causes plasticization faster and as a result, more energy dissipation is obtained versus other samples.