| The technology of energy dissipation has developed rapidly in the past few decades and has been widely used around the world.Buckling-restrained brace,as one of the most popular dampers,has developed into many new types since its birth to address miscellaneous structural& architectural requirements.In this paper,a new type of buckling-restrained brace-concretefilled elliptical steel tube buckling-restrained brace(CEST-BRB)-is proposed.This type of BRB also has the special performance of reducing windage resistance and has a certain application prospect in the area or location with large wind load.Through theoretical analysis,experimental study and finite element simulation,the configuration rationality,hysteresis behavior,energy dissipation capacity,global stability performance and other important parameters of CEST-BRB were analyzed and studied.The feasibility of this configuration was verified,and the global stability design method of CEST-BRB was proposed.The main work contents and conclusions are as follows:(1)Domestic and overseas literatures and books related to buckling-restrained braces were collected and classified in detail.The birth and development of BRB in recent 30 years were reviewed,which provides reference for scholars and practitioners around the world.(2)Four types of CEST-BRB scale specimens were designed and a total of 10 specimens were fabricated.The hysteretic performance and energy dissipation capacity of CEST-BRB were studied by using quasi-static low-cycle reciprocating experiments,and the rationality and feasibility of CEST-BRB configuration were investigated:1.No global buckling occurred in the four CEST-BRB specimens and the global stability was good.2.CEST-BRBs shown stable hysteresis performance and good energy dissipation capacity.3.The CEST-BRBs with normal dog-bone shaped core brace appeared local bulge in the process of large-displacement fatigue loading,while the CEST-BRBs with perforated core brace had good local stability.(3)The mechanical properties of four CEST-BRB test specimens were studied by finite element simulation analysis.Based on the results of finite element analysis,the causes of the phenomenon in the test were analyzed,and the improvement scheme was put forward.(4)The global stability of CEST-BRB was studied by theoretical analysis and finite element simulation.Deflection differential equations were used to calculate the deformation and forces of the core brace and the restraining unit,and the control parameters of the global stability of CEST-BRB were determined.With the assistance of finite element simulation,the theoretical analysis was verified and further studied. |
