十二边截面中空夹层钢管混凝土柱轴压试验研究

Experimental investigation of dodecagonal section double skin concrete-filled steel tubular columns under axial compression

试验中设计了4组共12个十二边形中空夹层钢管混凝土柱,通过对其进行轴压试验,研究各试件的受力过程及破坏形态,测得荷载-应变关系曲线,观察内外钢管的局部屈曲现象。研究结果表明:十二边截面中空夹层钢管混凝土柱在轴压作用下,外钢管出现局部屈曲,形态与圆形截面的畸变屈曲类似,没有发生棱角之间的平板部位的局部屈曲;内钢管也发生了局部屈曲,并且只能发生向内的屈曲变形;试件破坏为钢管鼓曲和内部混凝土压碎,表现出良好的延性。建议的十二边截面中空夹层钢管混凝土柱的承载力设计公式能较好预测其轴压承载力。

Experimental investigation of dodecagonal section double skin concrete-filled steel tubular columns under axial compression was conducted in this study and 12 column specimens were divided into four groups. The whole loading process and failure mode were observed. A series of curves of load-axial strain were also plotted and the local buckling of outer and inner steel tubes was studied. It is shown that the outer steel tube of dodecagonal section buckles like a round section steel tube and there is no local buckling occurred in the flat portion of the dodecagonal section. It is also shown that all the inner steel tubes buckle inward. All specimens fail by steel yield and concrete crush and behave good ductility. Design equations for dodecagonal section double skin concrete-filled steel tube under axial compression were proposed and agreed with the test results well.