偏心BRBFs的抗震性能分析

SEISMIC RESPONSE AND PERFORMANCE OF BUCKLING-RESTRAINED BRACED FRAMES

为了解偏心屈曲约束支撑钢框架(BRBFs)的抗震性能,运用pkpm设计软件设计门架式偏心BRBFs和人字形偏心BRBFs两种结构,基于大型有限元软件ANSYS对两种结构进行有限元数值模拟,分析了两种结构在基本烈度作用下的各层位移反应及层间位移角,结果表明,两种结构变形受低阶振型影响较大,沿高度呈倒三角地形分布,结构变形为弯剪形,各层位移及层间位移角均满足规范要求,体现出良好的抗震性能。构件产生塑性变形而耗能时,可以将结构构件等效为结构阻尼进行分析,介绍了等效阻尼比的求解方法。通过对罕遇地震作用下的两种结构的最大层间位移角、层间剪力及顶层位移时程的研究进一步评估两种结构的抗震性能,研究表明,在罕遇地震作用下,人字形偏心BRBFs的抗震性能较好。

In order to learn the seismic performance of eccentric buckling-restrained braced frames , two kinds of structures portal eccentric buckling-restrained braced frames and herringbone eccentric buckling-restrained brace frames, were designed with PKPM and numerically simulated based on finite element software ANSYS. The models＇ response sto- ry drifts, story shear forces under basic seismic intensity were measured. The deformation of the two structures present a shear-flexural type,and the low model has a great influention on the displacement of structure. Story drifts, story shear forces can both meet the seismic-resistent deflection demand, which indicates that the two kinds of structures both have good seismic performance. The components can be equivalent to the structure damping to be analyzed ,when they dissipate the energy through plastic deformation. The solution of calculating the equivalent damping ratio was presented. The seismic performance of the two strutures were evaluated furtherly through the investgation of toplevel displacement and story shear forces under 0.4g peak acceleration seismic ground motion , the result showed that the herringbone eccentric buckling-restrained brace frames performed better in earthquake-resistance.