Seismic Performance Of The Sleeved Column Of Buckling-Restrained Brace

With the rapid economic growth and increasing population, high-rise buildings have been pursuit by more and more people. The introduction of the Buckling Restrained Brace's gives a new concept of high-rise building structural and seismic design.BRB is a new kind of brace, in which the core cross-section can reach yield strength under tension and compression function. It can absorb and dissipate the seismic energy effectively to reduce the seismic response of structures. The initial form of BRB is composed of core material of low yield and steel pipe filled with concrete. In present, the core section type of the most popular BRB are"─"and"+". Recently,"T"-shaped cross section appeared. In this paper, the type of brace studied is the sleeved column of BRB, in which inner core and outer core are composed of steel pipe of different section sizes. Firstly, the theoretical analysis was done for the sleeved column of BRB, and the bearing capacity calculation formula of the total brace and the contact formula between inner core and sleeve were deduced, while the capacity properties of the brace was analyzed when the inner core occur high-level buckling. Through the test ,the seismic behavior of the six units BRB were studied, while the ultimate bearing capacity and energy dissipation capability of the BRB were analyzed, and the main factors affect the work performance is analyzed, such as the buckling-restrained ratio, prominent length of the inner core, gap and so on. The result shows that the sleeved column of BRB is of better bearing capacity and energy dissipation capability when the buckling-restrained ration is no less than 1.34.The stress procedure of the BRB were simulated and analyzed by using the finite element software. The result was compared to the results of experiment. The both are coincident. The result show that the friction impact is not obviously in the early of energy performance of the BRB through the analysis of friction impact between the sleeved columns. The correlative limited parameters of the BRB's were derived by comparing the experiment to the finite element analysis, which offers reference of the BRB for the future research and application.