中文摘要：

为适应巨型框架结构发展,提出了一种底部加强型多腔钢管混凝土巨型柱。为了比较它与相应普通多腔钢管混凝土巨型柱抗震性能的差异,进行了6个1/25缩尺的巨型柱模型在轴向压力或轴向拉力下的低周反复荷载试验研究。6个模型中：按底部截面构造区分,3个试件为底部加强型巨型柱模型,3个试件为相应普通巨型柱模型;按轴力作用方向区分,4个试件为轴压试件,轴压比分别为0.5、0.25,2个试件为轴拉试件,轴拉比为0.2。比较分析了各试件的承载力、刚度及其退化过程、延性、滞回特性、耗能和破坏特征。研究表明：底部加强型巨型柱与普通巨型柱相比,承载力、延性、耗能能力明显提高,刚度退化速度减慢,工作性能较稳定;轴压试件与轴拉试件相比,轴压试件抗震性能相对较好。

英文摘要：

Due to the development in mega-frame structure,a multi-cell CFST mega-column with strengthened bottom was proposed.Six 1/25 scaled multi-cell CFST mega-column models were tested under horizontal low cyclic loading,as well as the axial compressive load or the axial tensile load.According to different bottom constructions,three columns with strengthened bottom and three normal columns were designed.According to different directions of vertical axial loads,there are four columns under the vertical axial pressure with axial force ratio 0.5 and 0.25,and the other two columns under vertical axial tension with axial tension ratio 0.2.The load-bearing capacity,stiffness and its degeneration,ductility,hysteretic properties,energy dissipation capacity,and failure characteristic of the models were compared and analyzed.Results of the experiments show that the load-bearing capacity,ductility,energy dissipation capacity of the mega-columns with strengthened bottom are greatly improved,the speed of their stiffness degeneration is slower,and their work performance is more stable compared to the normal mega-columns.The seismic behavior of the new mega-columns under vertical axial pressure is better than that under the vertical axial tension.