Seismic Response And Performance Of Multistory Frames With Buckling-Restrained Braces

Braced frames have advantages in seismic regions because of its excellent lateral resistance system. Whether central or eccentric layout, braced frames always yield in compression, especially under seismic loading, which are damaged by the degradation of its stiffness and strength drastically.Improved by steel braces, Buckling-Restrained Brace (BRB), as a new member, provides the familiar stiffness and strength of a steel brace without the problem of compression buckling. BRB yields in tension and compression. In stronger earthquake, it exhibits stable and predictable hysteretic behavior, provides significant energy dissipation capacity and is an attractive alternative to protecting steel frames.The developed background,the prior research,the advantages,disadvantages and application of BRB are firstly clarified in this paper, besides, stability,design and factor governing the mechanical behavior of BRB is carried out in the term of theory and trail.In the following chapters, among steel frame, braced frame and BRB frame the analytic comparison of seismic responses in elastic and plastic stages is studied, which chooses the MIDAS/GEN. Response spectrum analysis indicates that BRB frames are suitable for M=8 or 9 earthquake regions. Time-history analysis of seismic responses (such as deformation, acceleration and hysteretic behavior) by comparison of small, moderate and strong earthquake shows that in the small earthquake, the BRB frames and the traditional braced frames have the similar performance, but in the moderate and strong one, BRB frames ,with enhanced stable hysteretic behavior, have shown to lead to satisfactory response.According to the above, BRBs can be used in the new structures, seismic reinforcement of existing ones and repairment of ones after earthquake.