【摘要】 利用SAP 2000软件建立柱脚刚接和铰接的结构数值模型，通过振型分解反应谱法研究了纵向内、外柱间支撑轴力比值随低跨中柱与边柱线刚度比λ₁和交接柱下柱与上柱线刚度比λ₂的变化趋势，再利用静力弹塑性方法研究该类结构的地震破坏模式。研究表明：（1）λ₁和λ₂的变化对纵向内、外支撑轴力比影响甚微，设计时可按比值均值考虑；对于交叉撑和人字撑，内、外支撑轴力比均值分别为1.07和1.04，即地震时结构内力在纵向柱列各支撑间几乎平均分配；（2）当柱脚刚接时，若λ₂>3则破坏为高跨上柱局部破坏，否则为整体破坏；当柱脚铰接时，若5<λ₁<7则破坏始于低跨中柱，否则破坏始于低跨边柱；（3）柱脚刚接时的整体破坏模式具有较好的延性和耗能能力，是理想的破坏模式。更多还原

【Abstract】 Using SAP2000 software, numerical models with fixed or hinged joints at the base were established at different values of λ₁ and λ₂. The axial force ratio between the longitudinal inner and outer columns as a function of λ₁ and λ₂ was studied using the mode decomposition response spectrum method. Then the seismic failure mode of this type of structure on the changing trend of the linear stiffness ratio of mid-column to side-column for the lower part and linear stiffness ratio of lower prop to upper pillar for intermediate columns λ₁ and λ₂ is studied using the static elastoplastic method. Research has shown that,（1） the change of λ₁ and λ₂ has little effect on the axial force ratio of longitudinal inner and outer bracing, and can be determined based on the average ratio during design. For cross and chevron bracings, the average axial force ratios of the inner and outer bracing are 1.07 and 1.04, respectively, indicating that the internal forces of the structure are almost evenly distributed among the bracings during earthquakes.（2） If λ₂ is greater than 3, the damage to the structure with fixed column base is local damage at upper column of intermediate columns, otherwise it is overall damage. If λ₁ is between 5 and 7, the failure of the structure begins with mid-column of the lower part, otherwise the failure begins with the side-column.（3） The overall failure mode for the structure with fixed column base has good ductility and energy dissipation capacity, making it an ideal failure mode of this type structure.更多还原