薄壁方形钢管再生块体混合短柱轴压试验研究

Axial behavior of thin-walled square steel stub columns filled with demolished concrete lump

为分析预测试件轴压承载力的有效性、轴压承载力提高系数和延性系数等轴压性能,以宽厚比、混合比、套箍系数及有无肋为试验主要研究参数,对15个薄壁方形钢管再生块体混合短柱进行轴压试验,分析试件的荷载-变形曲线、破坏形态、国内外相关公式。研究结果表明:在破坏阶段不带肋试件呈软化特性,带肋试件呈加劲特性;宽厚比相同时,带肋试件具有与全现浇试件相近的轴压承载力;混合比相同时,宽厚比为64、72带肋试件分别与宽厚比为72、80不带肋试件的轴压承载力相近;相关公式引入套箍系数计算精度较高;不带肋试件的轴压承载力提高系数与宽厚比和套箍系数呈抛物线关系,带肋试件呈线性关系,又均随混合比增大而减小;延性系数随套箍系数的增大而提高;通过对试验数据回归分析,推出不带肋和带肋薄壁方形钢管再生块体混合短柱的轴压承载力计算公式,其计算精度较好。

To analyze the effectiveness of predictions of the axial compression beating capacity of axially compressed specimens, the axial compressive bearing capacity enhancement coefficient, and ductility coefficient, with the main parameters being width-thickness, mixed ratio, hoop coefficient, fifteen thin-walled square steel stub columns filled with demolished concrete lump are tested under axial loading. The results show that during in destruction no ribbed stiffener columns show softening behavior and ribbed stiffener columns show strengthening phenomenon; the axial loading bearing capacity of the fibbed stiffener columns is similar to the columns filled with cast-in-situ concrete when the width-thickness is the same, and the axial loading bearing capacity of the ribbed stiffener columns of width-thickness of 64 and 72 is similar to the fibbed no stiffener columns of width-thickness of 72 and 80 when the mixed ratio is the same ; the related formulas with hoop coefficient have higher calculation accuracy; the axial compression beating capacity enhancement coefficient of no ribbed stiffener columns is parabolicly related with width-thickness and hoop coefficient, while the fibbed stiffener columns has linear relations, and all are reduced with the decrease of the mixed ratio; ductility coefficient is enhanced with the decrease of hoop coefficient; through regression analysis, the axial compression beating capacity calculation formula for thin-walled square steel stub columns filled with demolished concrete lump has good accuracy.