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对8个受纯扭和压扭循环加载作用下的钢管混凝土柱的拟静力试验,研究不同截面、钢筋比和轴压比的钢管混凝土柱的扭转性能。试验结果显示:纯扭和压扭循环加载下的钢管混凝土的滞回曲线很饱满,从而证明钢管混凝土柱有很好的抗震能力。钢管混凝土柱的卸载刚度和初始弹性刚度相等。低压缩负载可以提升钢管混凝土柱的扭转能力并使其有很好的延性。但高压缩负载则会降低钢管混凝土柱的扭转能力。钢管混凝土柱受纯扭作用时,内填混凝土柱将会承受螺旋形的斜向压力,且内填混凝土斜向压力的轴向分力与钢管的轴向张力相等,从而满足截面的轴向荷载平衡条件,并在钢管上产生轴向应变。当钢管混凝土柱受纯扭和压扭共同作用时,剪切应变与截面的旋转角度呈现了很好的线性关系。根据试验结果和现有文献对钢管混凝土柱的扭转性能进行初步分析。
Quasi-static tests on eight concrete-filled steel tubular columns subjected to pure torsional and compression-torsional cyclic loading were carried out to study the torsional behavior of concrete-filled steel tubular columns with different cross-sections, ratio of steel bar and axial compression ratio. The experimental results show that the concrete filled steel tube under full torsional and compression-torsional loading has a very full hysteresis curve, which proves that the concrete-filled steel tube has good anti-seismic capacity. The unloading rigidity and initial elastic rigidity of CFST columns are equal. Low compression load can improve the torsion of steel concrete columns and make it have good ductility. However, high compressive load will reduce the torsional capacity of concrete filled steel tubular columns. When the concrete-filled steel tube column is subjected to pure torsional action, the filled concrete column will be subjected to the helical oblique pressure, and the axial component of the diagonal pressure of the concrete filled in will be equal to the axial tension of the steel pipe so as to satisfy the axial load of the section Balance conditions and produce axial strain on the steel pipe. When the concrete-filled steel tubular columns are subjected to pure torsion and compressive torsion, the shear strain and the rotation angle of the section show a good linear relationship. Based on the test results and the existing literature, the torsional behavior of concrete filled steel tubular columns is analyzed.