Theoretical Analysis And Experiment Study On Buckling-restrained Brace

Choosing the lateral force resisting system is an important part in the selection of building structures. The earthquake resistance performance of frame construction is generally good, and can achieve the very good ductility. However, there is a big level deformation when earthquakes occur, which makes it easy to create the non-structural unit's destruction To some degree, the frame-bracing system increases the anti-side ability of a frame, but in big earthquake, the brace is easy to have compression buckling, causing damage to the brace itself or the connections, and it is not conducive to energy dissipation. Traditional braces'solution is increasing cross-sectional area of the brace, which will cause the waste of materials. Therefore, the experts and the scholars propose the Buckling-Restrained Brace (BRB for short) which can prevent itself from buckling. Through reasonable design, BRB will yield and consume energy firstly instead of buckling, performing good seismic behavior in big earthquakes. But at present, the core technologies of BRB are mostly owned by individuals, and also core unit of BRB is mostly made by low yield steel which is on low supply and expensive. As a result, BRB has not obtained a wide range promotion in domestic market.In this paper, the basic theory of BRB, including the constitutes, basic principles, classifications, advantages and disadvantages are introduced firstly. Then the work principle in different design situations and stability of BRB are analyzed thoroughly, and the related formulas are derived, including requirements of overall stability, core element stability and connection stability. Large-scale test of newly developed low carbon steel circular tube BRB is performed, and the test data are collected and analyzed. The test shows that the newly developed BRB has a better capacity in energy dissipation. Further recommendations for improvements are put forward in the remaining problems. Depending on the requirements of energy dissipation in seismic design codes abroad and in, the designing method of BRB is discussed from the aspects of basic requirements, design features, support for layout, design procedure and others, providing some references for the engineers. At last, depending on the domestic and foreign development and application of BRB, some proposals are put forward in further research, application and popularization in our country as well as forecasting the future trend of development.