The Analysis Of Hysteretic Behavior And Collapse Mechanism For V-Shape Eccentrically Braced Semi-rigid Steel Frame

Many achievements prove that semi-rigid steel frames have the excellent seismic performance. But it also has some imperfection such as lower lateral stiffness and larger lateral deformation. Semi-rigid steel frame with eccentric brace is a new type of seismic structural systems which enhances the lateral stiffness of framework, and researches about it are rare.This paper mainly analyzed the hysteretic behavior and collapse mechanism of V-shape eccentrically braced semi-rigid steel frame. The study includes cyclic test and finite element analysis with ANSYS. The latter is the primary part. The former is adjunctive part, and was used to verify the reliability of the latter.Test results of V-shape eccentrically braced steel frame show that the hysteresis curves of frame with welded connections and end plate connections are very full and it has the best energy-dissipation. Because of the earlier fracture of T section steel flange, the plastic developing of links isn't enough, T section steel joint frames has the worst energy-dissipation. Angle steel joint frames also have worse energy-dissipation.The finite element analysis with ANSYS mainly investigates the relations between the hysteretic behavior of the semi-rigid steel frame and the major facts. The major facts include the rotation stiffness of beam-column connections,the brace type and the span and layer numbers of the frame.The analysis shows that the rotation stiffness of beam-column connections have a significant effect on the hysteretic behavior of eccentrically braced frame, and higher the connection stiffness, the better the hysteretic behavior.The destruction of eccentrically braced semi-rigid frame occurs at the link beams,and higher the connection stiffness, the better the plastic developing of link beams. Compared to unbraced frame, eccentric brace increase lateral stiffness of semi-rigid steel frame significantly and reduces the lateral deformation.Finally, the characteristics of the V-shape eccentrically braced semi-rigid steel frame is summed up based on the results of experimental research and the finite element analysis. And this paper also gives some advices to later research according to its shortage.