Study On Mechanical Performance Of Buckling-Restrained Braced And Aseismic Behavior Of Its Steel Frame

At present, the steel structure is mostly the non-braced, the center-braced steel frame and the eccentric-braced frame at home. The beam and column sections of non-braced steel frame are usually amplified to satisfy the lateral displacement because of its flexible lateral stiffness. The center-brace is always buckling under strong earthquake which makes the lateral stiffness and dissipation ability of the frame falling down rapidly. The eccentric-braced frame has resolved the problems appearing on above-mentioned structures to a certain extent, but the eccentric-brace is still buckling under massive earthquake and have a asymmetric hysteretic behavior under tension and compression. So those structures mentioned above only satisfy the request of intensity, stiffness and dissipation partly, which is difficult to reach the request of the aseismic optimization design.As a sensitive energy dissipation component, the Buckling-Restrained Braced (BRB) is superior to traditional braces because of its stable hysteretic behavior and excellent dissipation ability under earthquakes, and the aseismic behavior of BRB steel frame is improved effectively. The BRB can reach fully sectional yielding of the core under compression, its stable hysteretic behavior keep the BRB braced steel frames working well under earthquakes.Firstly, analyzing the study actualities about the BRB around the world, the development and the behavior of BRB are introduced. Based on this, the stability analysis of Buckling-Restrained Brace is carried out, and the limited conditions are put forward.Next, nonlinearity is introduced in the contact analysis by finite element software ANSYS to precisely simulate the work process of the BRB. The rigidity of the out tube, the concrete intensity, the gap and the slenderness ration, which affect the performance of the BRB steel frame are analyzed to some extent.Using the SAP2000 structure analysis software, the paper carried out time history analysis and Push-over analysis on the non-braced, the centre-braced steel frame as well as the BRB steel frame and gave the failure modes of the three structures respectively. The results show that the BRB steel frame possesses excellent energy dissipation ability and ductility, which reduced the destruction of the whole steel frame during earthquake.