为了研究中心支撑钢框架结构的抗震性能,通过OpenSees和SAP 2000有限元分析软件对1幢12层的中心支撑钢框架结构进行数值模拟分析.通过静力弹塑性(Pushover)和低周往复加载分析,研究了中心支撑钢框架结构的破坏形式以及支撑构件破坏的先后顺序,探讨了OpenSees中构件单元类型和单元尺寸对结构基底剪力-顶点位移曲线的影响以及框架在低周往复荷载下的抗震性能.分析结果表明:中心支撑钢框架结构在破坏时,支撑先发生屈曲,且随着支撑构件的屈曲,钢框架承载能力下降,底层支撑受力最大;采用不同类型的非线性纤维单元和不同的单元尺寸对Pushover曲线都有一定的影响;钢框架滞回曲线饱满,具有良好的抗震耗能能力.
In order to study the seismic behavior of the concentrically braced steel frame structure(CBSFS), in this paper the numerical simulation was performed for a twelve-story CBSFS by the use of OpenSees and SAP 2000. Through the Pushover and quasi-static analysis,the failure modes of the CBSFS,the damage order of the bracings and seismic behavior of the frame under quasi-static load were researched; meanwhile, the influence of element type and element size for members in OpenSees on the base shear-top displacement of the structure were also investigated. The results showed that:while the concentrically braced steel frame structure subjected to failure, the braced members occurred buckling firstly;with the instability of the bracings,the bearing capacity of frame decreased,and the internal force of the bracings was the largest at the bottom story; the element type of nonlinear fiber element and element size of members would influence the Pushover curves to some degree;the steel frame,with full hysteretic curve,had a good energy dissipation capacity.