复合钢管混凝土轴压柱承载机理分析

Study on behavior of concrete filled double steel tubular columns under axial compression

基于混凝土的塑性损伤模型对外方内圆型复合钢管混凝土柱轴压试件的承载机理进行研究,对比了复合钢管混凝土柱和单钢管混凝土柱在加载过程中横截面上混凝土的纵向应力分布规律,揭示了该组合构件的承载机理:复合钢管混凝土柱中核心混凝土受到内外层钢管的双重约束作用,因此,核心混凝土的轴向应力比单钢管混凝土柱的纵向应力大,极限承载力也随之增大;但夹层混凝土的纵向应力与单管混凝土纵向应力两者相差不大;在此基础上分析钢管壁厚及混凝土强度等级等参数对复合柱力学性能的影响.

Based on a plastic-damage model for concrete,the numerical simulation of the concrete filled square-round double steel tubular columns under axial compression is carried out by finite element software ABAQUS.The axial stress distribution of the concrete section for a double steel tubular column and a single one during the loading process is analyzed for comparing purpose.And the mechanical performance for this newly proposed composite column is explored.The axial stress of the columns confined by the outer and inner steel tubes is larger than that of the single one and thus leads to a higher ultimate bearing capacity.The results also indicate that the axial stress in the sandwich concrete for the double steel tubular column is close to that in the concrete of a single steel tubular column.An extensively parametric study,including tube thickness and concrete strength level,is also carried out.