Research On Simplified Design Method Of Multy-Story Frame Structure With Buckling Restrained Brace

Buckling-restrained brace (BRB) is a new type of prospective energy dissipation component, which can improve the seismic performance of the structure, and which is widely used in the building of earthquake zones. After the WenChuan Earthquake the government improved the earthquake fortification level for primary and secondary school, and launched the project of the safety of primary and secondary schools and dormitories. Especially in Yunnan Province,the government provided that more than three layers of school buildings and dormitories must use isolation or energy dissipation technology. The study of the design method of buckling.restrained brace frame has become a very important problem,which can promote the application of BRB in practice.Firstly, this article mainly elaborate the development and principles of BRB, and seismic behaviors of BRB frames. And it describes in details of the structure and working principle of the Buckling Restrained Brace,and methods of buckling.restrained brace frame.Secondly, the author proposes a simplified design method of buckling.restrained brace frame in Chapter 3,which is based on design seismic performance of structure and has strong practicability and maneuverability. At the same time, the author obtains a series form that can directly applied in the design process. These forms have a high precision, and it can be used to choose the ductility coefficient and additional elastic stiffness ratio which can meet the target displacement reduction ratio.Thirdly, the main design steps and process of the simplified design method were give in Chapter 4.First preliminary selected target displacement angle to calculate the expected target displacement decrease rate of the structure. Secondly, using tables to get the ductility coefficient and additional elastic stiffness ratio which can meet the target displacement reduction ratio.Then, put the additional elastic stiffness ratio translated into the additional elastic stiffness of each layer Finally, calculating the demand of buckling restrained brace of each layer.Fourthly, the author introduces tow BRB frames in Chapter 4.Through those example to illustrate the feasibility and practicality of this design method. Those tow example were design by the simplified design proposed in this paper with different target layer displacement angles and BRB arrangement principle.Fifthly, the seismic behaviors of those example were study, and 7 seismic waves and 3 seismic waves are input to MIDAS.GEN to run the analysis. The analysis results show that the simplified design has high precision and feasibility. The structure met the expected targets in moderate earthquake, and also showed a good seismic performance in rare earthquake.Finally, the summary of the main sections of this article is made. At the same time, the author obtains some useful conclusions. Combined with research and engineering applications, problems to be solved in the subject as well as the further development directions are proposed to enspirit the research craze in the future.