带内拉架方钢管混凝土柱轴压试验研究

EXPERIMENTAL STUDY ON AXIAL COMPRESSIVE PROPERTIES OF CONCRETE-FILLED STEEL SQUARE TUBULAR COLUMNS WITH INNER TIE-BAR FRAMES

针对一种“半装配式”结构,设计了一种带内拉架的钢管混凝土方柱。为了降低该钢管混凝土柱成本,确定其用钢量的最优比例,按正交试验设计方法设计了9组试件及3组对比试件进行短柱轴压试验。试验结果表明:同等用钢量条件下,设置内拉架可有效提高柱轴心受压承载力;钢管、竖向钢筋、水平拉结筋三者之间用钢量比例为45∶35∶20时,构件轴压承载力较高;水平拉结筋用钢量占比宜不小于20%,过小会导致水平拉结不足造成构件轴压承载力明显降低;总用钢量相同时,是否设置内拉架,对构件延性影响不明显;对于装配式结构,预制件的制作误差及混凝土浇筑质量对构件承载力的影响不可忽视。

A partially fabricated concrete-filled steel square tubular column with a inner tie bar frame was designed.In order to reduce the cost and determine the optimal proportion of steel mass consumed in the structure,according to the orthogonal experimental design method,9 groups of specimens and 3 groups of control specimens were designed for axial compression tests of short columns.The results indicated that the bearing capacity of the new kind of column subjected to axial compression could be improved effectively in the same consumption of steel.The axial compressive bearing capacity of the member was higher when the steel consumption of steel pipes,vertical rebars and horizontal tie bars was about 45∶35∶20.If the ratio of horizontal tie bars was too small,a significant reduction in axial bearing capacity would take place due to insufficient tie forces,and the recommended value was not less than 20%.Besides,the influence with or without tie-bar frames on the ductility of the structure was not obvious in the same total consumption of steel.For pre fabricated structures,the influence of the fabrication errors of members and the quality of cast concrete on the bearing capacity of members could be ignored.