石  艳，郭  兵，田海兰
    (山东建筑大学土木工程学院，济南250101)

[摘要] 将偏心支撑与半刚接钢框架相结合，是一种新型的框架支撑体系。偏心支撑可以弥补半刚接钢框架的刚度不足，同时又不降低其延性和耗能能力。运用ANSYS有限元分析软件，建立了4榀6层的半刚接钢框架（1榀框架无偏心支撑，3榀框架有偏心支撑）有限元模型，对框架试件进行模态分析。研究节点初始刚度、支撑条件等因素对框架自振周期的影响。根据分析得出：偏心支撑半刚接钢框架的刚度主要由支撑提供，梁柱的半刚性连接对结构的自振周期无显著影响。在相同参数下，支撑类型对结构自振周期有影响。
[关键词] 偏心支撑钢框架；半刚性连接；ANSYS；模态分析

    Modal analysis of eccentrically braced semi-rigid steel frames
    Shi Yan, Guo Bing, Tian Hailan
    ( Department of Civil Engineering, Shandong Jianzhu University, Jinan 250101, China)

Abstract: There formed a new type of braced resistant steel frame, which combined eccentrically braces and steel frames with semi-rigid connections. Eccentrically braces increase the lateral stiffness of steel frames with semi-rigid connections and meanwhile maintain its ductility and energy dissipations. ANSYS was employed to model semi-rigid steel frames with four different support types. Modal analysis of the frames was studied to investigate the dynamic property of eccentrically braced semi-rigid steel frames, which was influenced by rotational stiffness of connections, eccentrically braced type and so on. It is concluded that the stiffness of eccentrically braced semi-rigid steel frames is supported mainly by the supports. The semi-rigid connection has no significant effect on the natural cycle. The types of eccentrically braced have effect in the same parameters.
Keywords: eccentrically braced steel frame; semi-rigid connection; ANSYS; modal analysis