配筋空心圆钢管高强混凝土轴压短柱工作机理分析

Mechanical Behavior Analysis of Reinforced Hollow High Strength Concrete Filled Circular Steel Tubular Short Columns under Axial Loads

目的 提出一种配筋空心圆钢管高强混凝土新型组合柱,分析其在轴向荷载作用下的工作机理,以解决空心钢管混凝土柱空心率较大和延性差等问题。方法 对配筋空心圆钢管高强混凝土短柱进行轴压试验,利用ABAQUS有限元分析软件建立组合柱的有限元模型,以试验结果验证有限元模型的准确性。对组合柱的受力工作机理进行分析,重点研究其在轴向荷载作用下的受力过程、各组分分担内力比例和应力状态。结果 与空心圆钢管高强混凝土柱相比,未配置普通钢筋的试件峰值承载力提升了6.37%、DI提高了6.64%、SI提高了3.59%,配置普通钢筋的试件峰值承载力提升了13.31%、DI提高了8.12%、SI提高了5.68%。整个受力过程中,管柱混凝土和夹层混凝土承载的内力比例分别为36.2%~39.7%和29.0%~30.6%。结论 配置普通钢筋的试件具有更高的承载能力和延性能力;夹层混凝土和管柱混凝土在加载过程中为主要受力组分;钢筋在加载前期基本不承担内力,进入塑性强化阶段才开始发挥作用。

A novel composite column of reinforced hollow circular steel tubes filled with high-strength concrete(RHCFST)is proposed,and its mechanical behavior under axial load is investigated.The aim of this study is to address the issues of large hollow ratio and poor ductility commonly observed in hollow concrete-filled steel tubular(HCFST)columns.Experimental testing was conducted on reinforced hollow circular high-strength concrete-filled steel tubular short columns subjected to axial load.Subsequently,a finite element model of the composite column was developed using ABAQUS software,and its accuracy was validated against experimental data.The mechanical behavior of the composite column was analyzed,with a particular focus on the stress distribution under axial load,the distribution of internal forces among different components,and the overall stress state.Comparative analysis revealed that improvements were observed in the RHCFST columns compared to the HCFST columns,with the ultimate bearing capacity increasing by 6.37% for specimens without ordinary steel bars and by 13.31% for specimens with ordinary steel bars.Additionally,notable enhancements were observed in the ductility index(DI)and strength index(SI).Throughout the loading process,the proportions of internal forces carried by the column concrete and the sandwich concrete were determinedto be 36.2%~39.7% and 29.0%~30.6%,respectively.The proposed RHCFST columns,particularly those incorporating ordinary steel bars,demonstrated superior bearing capacity and ductility.Notably,sandwich concrete and column concrete were identified as the primary load-bearing components during loading,while the steel bars remained inactive in bearing internal forces during the initial loading stages,only becoming effective during the plastic strengthening phase.