Background: The poor performance of steel flexural joints in past earthquakes and the high costs of repair and reconstruction have highlighted the need to develop joints that can concentrate the damage in a replaceable member and prevent damage to the beam and column. Therefore, the present study aimed to evaluate the seismic performance of a steel flexural joint equipped with a gutter fuse.
Methods: Nonlinear numerical analyses under cyclic loading were performed in Abaqus software. In addition to the base model (P20), the effect of the fuse flexural capacity, beam flange and web thickness, column connection and double plates, and the distance between the two free edges of the beam were investigated parametrically. The evaluation criteria included equivalent plastic strain (PEEQ), flexural capacity, energy absorption, stiffness, ductility, and hysteresis curves.
Results: The results showed that in the P20 model, the plastic hinge was completely formed in the gutter fuse and the beam and column remained in the elastic range; In such a way that the connection provided about 98% of the plastic capacity of the beam. Reducing the thickness of the beam flange or web caused damage to be transferred to the main members and decreased performance, while observing the capacity-based design ensured the concentration of inelastic deformations in the fuse. Also, the simultaneous removal of the continuous and double plates reduced the energy absorption and bending capacity of the connection by 45.56 and 42.82%, respectively. Increasing the distance between the two free edges of the beam to 60 mm also created a suitable balance between strength, ductility and energy absorption while maintaining the concentration of plastic strain in the fuse.
Conclusion: The findings of this study showed that the proposed connection equipped with a gutter fuse, if observing the capacity-based design and using appropriate reinforcement plates, has desirable seismic performance, high interchangeability and appropriate capacity to reduce damage and repair costs after an earthquake, and can be used as an efficient option in the design of steel bending frames.