两种支撑-钢框架体系抗震性能对比分析

Comparison on Seismic Performance between Two Kinds of Bracing-steel Frame Structure

采用有限元分析软件SAP2000,在钢框架中分别布置普通支撑和屈曲约束支撑(下称BRB),模拟8度罕遇地震作用下结构的弹塑性时程反应,并对结构位移响应、层间延性需求、顶层加速度、基底剪力及塑性铰出铰顺序及分布进行分析。结果发现:BRB-钢框架体系两个方向最大层间位移角比普通支撑-钢框架体系分别小12.6%和17.5%,顶层位移峰值分别减小9.3%和19.4%;在允许延性需求为4.0时,BRB-钢框架体系和普通支撑-钢框架体系延性需求最大值分别为3.88和4.69;结构两个方向顶层加速度峰值分别减小27.6%和10.4%,基底剪力两个方向分别小了34.0%和26.3%;二者在地震作用下塑性铰初始出现时间差异不大,但塑性铰在BRB-钢框架构件中发展较慢,最终普通支撑-钢框架中部分节点和柱子完全丧失承载能力,而BRB-钢框架体系依然处于安全极限范围内。

Using SAP2000 finite-element-software,the time-history analysis of ordinary bracing-steel frame and buckling-restrained-brace（ BRB）-steel frame are carried out under eight degree rare earthquake. The displacements response, ductility demand, top-floor accelerations, base shear force and plastic hinge are compared. It turns out that under the rare earthquake action,the maximum inter-story displacement angle in X and Y two directions of BRB-steel frame is less 12. 6 percent and 17. 5 percent than the ordinary bracing-steel frame,and the top floor displacement is less 9. 3 percent and 19. 4 percent respectively. The ductility demand of the BRBstell frame is 3. 88,and the bracing-steel frame is 4. 69. The acceleration of the top in BRB-stell frame can reduce27. 6 percent and 10. 4 percent,and the base shear can reduce 34. 0 percent and 26. 3 percent respectively. The times of plastic hinge occur in two frame are no notable difference,however,the development of plastic hinge in BRB-steel frame is slower,and there are some column and node in ordinary bracing-steel frame be broken,but the BRB-steel frame is secure.