| Brace, as an excellent lateral force resistance system, has been widely welcomed and largely applied to anti-seismic design, however, after the earthquake in Northridge in 1994 and the earthquakes in Osaka and Kobe in 1995, the research found that the premature buckling of large number of braces is an important reason to destroy structure. Japanese engineering field put forward a new brace----buckling-restrained brace (BRB) in order to improve the anti-seismic performance of brace.BRB, by means of reasonably establishing constrained mechanism on the periphery of common braces to limit its compression buckling instead of limiting axial deformation, finally makes the total cross-section in both tension and compression yield but does not make the brace buckle. BRB, by its own rigidity and hysteretic energy produced by the yielding earlier than the structural main body, can minimize or even avoid the damage of main body in earthquake.The production, development and application of BRB is firstly clarified in this paper, besides, stable analysis and construction design are used for BRB in terms of theory and trail. On this basis, the principle of energy dissipation and seismic reduction of buckling-restrained braced frame is deducted to expound through the theory; and analytical method for the practical design of this kind of structure is posed. Finally as the example of concrete project, the structural design is analyzed and construction technique is researched in this paper.In the chapter about structure design and analysis, SATWE software is chosen in this paper for the elastic design in accordance with China code demands; and time- history analysis method is used for the analytical comparison of energy dissipation and seismic reduction between BRB structure and common brace structure. The result of time-domain analysis shows the two points: Structural flexibility design is reasonable which accords with the anti-seismic demands in the code of China; and BRB mechanism contains a conspicuous seismic reduction effect compared with common brace structure.Aimed at the characteristics of BRB performance, the relative brace design and manufacture and construction technology and method are posed. However, it is still waiting for being improved seeing that the domestic BRB theory and experimental result are relatively scarce, besides the actual projects are seldom used. According to the above, the seismic reduction mechanism of BRB is specific, and the seismic reduction effect is obvious, safe and economically reasonable, so BRB can be used in the structures with different earthquake intensity and anti-seismic demands. It can also be used both in single-story building and in the more-story building; and it is not only suitable for the newly built building but for the built building in terms of anti-seismic reinforcement and post-seismic restoration. Therefore, it contains a wide prospect. |
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