中文摘要：

为了研究塑料制品代替钢管作为方中空夹层钢管混凝土中的内管对其轴压性能的影响,设计了内管为PVC管、PPR管、圆钢管的方中空夹层钢管混凝土试件共5根,对所有试件进行了轴压试验;并分析了其整体、核心混凝土、内管的破坏形态、荷载-纵向应变关系曲线及组合弹性模量,试件的轴压全过程运用有限元软件ABAQUS模拟。结果表明：PVC管受到压力时呈脆裂破坏,而PPR管和圆钢管有较好的抵抗塑性变形的能力;按极限承载力和组合弹性模量由大到小的排列是：钢内管试件,PPR内管试件,PVC内管试件;有限元模型能够较好地模拟所有试件的前期刚度和钢内管试件的极限承载力;PVC管和PPR管在轴压全过程中承担的轴向荷载及其与混凝土的相互作用几乎为零。

英文摘要：

Five square concrete-filled double skin steel tubes（SCFDST） were made to investigate the impact of using plastic instead of steel as inner tube on axial compression mechanics behavior of SCFDST, three types of inner tube were included, i. e., steel tube, PVC tube and PPR tube. All specimens were under axial compression, the failure modes about whole and internal, N-ε curves and composite elastic modulus have been analyzed. The whole process of axial compression of 5 specimens were simulated by the finite element method（FEM） software ABAQUS. The results show that, PVC tube show its brittleness under pressure, but PPR tube and steel tube have good capacity to resist the plastic deformation. The sequence is inner steel tube specimen, PPR tube specimen and PVC tube specimen according to the ultimate bearing capacity and composite elastic modulus order. Stiffness in earlier stage of all specimens and the ultimate bearing capacity of SCFDST with steel tube calculated by FEM model are in good agreement with those measured by experiment. PVC tube and PPR tube only undertake little axial load in the whole process compared with steel tube, and the interaction with sandwich concrete is negligible.