非一体型钢管混凝土柱轴压承载力的有限元分析

Finite element analysis on axial bearing capacity of non-integrated-type concrete filled steel tubular column

为了研究钢管与混凝土之间相互作用对钢管与混凝土间无黏结非一体型钢管混凝土柱轴压承载性能的影响,以未考虑与钢管相互作用的素混凝土和考虑与钢管相互作用的混凝土为对象,钢管径厚比为25～67,建立了7个非一体型钢管混凝土柱有限元分析模型,进行三维有限元分析,并与以往试验结果比对.结果表明：对于非一体型钢管混凝土柱模型,考虑钢管与混凝土相互作用时的初始刚度、最大轴力值与试验结果基本一致;不考虑时的初始刚度、最大轴力值小于试验结果;随着钢管厚度增大,钢管径厚比减小,其相互作用增大明显.当钢管径厚比小于25时,若考虑相互作用的破坏形式,建议混凝土按三轴膨胀破坏设计.

This paper presents a study of the axial compression bearing capacity of non-integrated-type concrete filled steel tubular column(CFST column)considering the bonding between steel tube and concrete or not.The special considerations are placed on the influence of the interaction between the tube and concrete and taking the diameter-thick ratio of the steel tubule is 25-67.The three-dimensional finite element analyses are conducted and the numerical results are compared with the experimental results.The following conclusions can be obtained.First,for non-integrated-type CFST column model,the initial rigidity,the maximum axial force agree well with the experimental results when considering the interaction between steel and concrete;otherwise,the numerical values are smaller than the experimental ones.Secondly,with the increasing of the steel tube thickness,and the decreasing of the pipe diameter to thickness ratio the interaction increases significantly.Thirdly,triaxial compression failure criterion is recommended for the concrete design when considering the interaction as the pipe diameter to thickness ratio less than 25.