核心型钢混凝土柱轴压性能试验研究

为研究核心型钢混凝土(CSRC)柱轴压性能及轴力分配规律，进行了5根CSRC柱和2根钢筋混凝土(RC)柱的足尺轴压静力试验。试验结果表明：CSRC柱的承载力和变形能力随配钢率的增加而明显增加；设置配钢率为2.5%和3.2%的核心型钢，试件轴向承载力可分别提高12.7%和23.4%，试件变形能力分别提高36.0%和33.1%。试件各组成部分所承担的轴力占总轴力的比例随轴向变形的发展呈非线性变化。在弹性阶段，试件各部分承担轴力基本按材料弹模与相应截面积的乘积线性分配；在塑性阶段，混凝土承担轴力占总轴力比例逐渐降低，核心型钢承担轴力占总轴力比例逐渐增大，最大可达40.1%。CSRC柱轴压承载力可采用考虑箍筋约束作用的简单叠加法进行计算。

Experimental study on axial compression behavior of core steel reinforced concrete columns

Five core steel reinforced concrete (CSRC) columns and two reinforced concrete (RC) columns were tested under monotonic axial compression to investigate the axial compression behavior and axial load distribution law of CSRC columns. The main parameters were the core steel ratio, the concrete strength, and the volumetric stirrup ratio. It is indicated that the bearing capacity and deformation capacity of the CSRC columns are increased with the increase of the core steel ratio. As for the CSRC columns with a core steel ratio of 2.5% and 3.2%, the bearing capacities are 12.7% and 23.4% higher than those of the RC columns, and the deformation capacities are 36.0% and 33.1% higher than those of the RC columns, respectively. The ratio of the axial load carried by different components of the CSRC column develops nonlinearly with the increase of axial deformation. At the elastic stage, the axial load carried by different components is proportional to the product of the material modulus and the corresponding sectional area. At the plastic stage, the ratio of the axial load carried by the concrete decreases, while the ratio of the axial load carried by the core steel increases. The maximum ratio of the axial load carried by the core steel is 40.1%. The bearing capacity of CSRC columns can be calculated with the superposition method while considering the confining action of the stirrups.