方中空夹层钢管混凝土压扭构件的试验及有限元计算研究

EXPERIMENT AND FINITE-ELEMENT CALCULATION STUDY ON CONCRETE-FILLED DOUBLE SKIN STEEL TUBULAR MEMBERS UNDER COMPRESSION AND TORSION

以长细比、空心率和轴压比为变化参数,对7根方中空夹层钢管混凝土和1根方实心钢管混凝土压扭构件进行试验研究。试验结果表明:所有试件表现出良好的延性,夹层混凝土出现约45°的斜裂缝,混凝土未破碎;当轴压比较小(n≤0.3)时,轴压比越大,抗扭承载力越大;当轴压比较大(n>0.3)时,轴压比越大,抗扭承载力越小。采用有限元方法对试件的扭矩-转角关系曲线进行模拟,两者符合良好。

A total of seven concrete-filled double skin steel tubular（CFDST） members and one concrete-filled steel tubular（CFST） member were tested under compression and torsion. The outer steel tube of CFDST and CFST members was square hollow section （SHS） , and the inner steel tube of CFDST members was circular hollow section （CHS）. The test results showed that all the specimens exhibited good ductility. The sandwiched concrete was not broken, and approximate 45° diagonal cracks appeared. When the axial compression ratio was small（ such as n ≤ 0.3 ） , torsional capacity of the test specimen increased as the axial compression ratio increased. When the axial compression ratio was large （ such as n 〉 0. 3 ） , torsional capacity of the test specimens decreased as the axial compression ratio increased. Torque versus angle curves of the test specimens calculated by the finite element method agreed well with experimental ones.