中空夹层薄壁钢管混凝土短柱轴压性能研究

Study on the Behavior of Concrete-Filled Double-skin Thin-Walled Steel Tubular Stub Columns Under Axial Compression

进行了9个轴压短柱的试验研究,考察空心率和径厚比对方套圆中空夹层薄壁钢管混凝土轴压短柱力学性能的影响。试验发现中空夹层薄壁钢管混凝土轴压短柱具有较好的延性和较高的承载力。接着对中空夹层薄壁钢管混凝土轴压短柱进行了数值模拟,数值模拟结果与实测结果吻合良好。机理分析表明:外钢管的约束效果主要集中在角部,纵向加劲肋可很好地提高外钢管的承载力。参数分析表明中空夹层薄壁钢管混凝土轴压短柱的承载力随着钢管屈服强度、混凝土强度或径厚比的增大而增大;构件的延性随着空心率的增大而增大。最终建议了中空夹层薄壁钢管混凝土轴压短柱承载力的简化计算公式。

An experimental study on nine stub columns under axial compression is carried out. The effects of the hollow ratio and diameter to thickness ratio on axial compressive behavior of concrete-filled double skin thin-walled steel tubular（ CFDSTST） stub columns with an outer square tube and an inner circular tube are studied. The test results indicate that CFDSTST stub columns have many advantages such as good ductility and high strength. The numerical simulation of CFDSTST stub columns under axial compression is then carried out. The predicted results agree well with the test data. The mechanical analysis indicates that the confining effect on concrete is focused on the corner of the steel tube,and the longitudinal stiffeners can effectively enhance the load bearing capacity of the square steel tube. However,the parameter analysis indicates that with the increase of yield strength of steel tubes,concrete strength or diameter to thickness ratio,the load bearing capacities increase. Also,a higher hollow ratio leads to higher ductility. Finally,a simplified calculation equation is proposed to predict the axial compressive resistance of CFDSTST stub columns.