钢管壁开洞组合柱试件轴心受压性能试验研究

Experimental study on axial compressive behavior of composite column specimens with openings on steel tube wall

为研究圆钢管壁开洞率对钢筋混凝土梁-钢管混凝土组合柱节点核心区轴心受压性能的影响,进行了14个钢管壁开洞和4个钢管壁不开洞的钢管混凝土组合柱试件的轴心受压试验。试验结果表明:钢管壁开洞率不大于50%时,试件的轴心受压承载力没有显著降低;钢管壁开洞率为50%且壁厚由8mm增大到12mm和14mm时,试件轴心受压承载力有较大提高;设置加劲板加强钢管壁洞口四周的试件,轴压力-纵向应变曲线在峰值点后下降平缓,试件的塑性变形能力明显提高。考虑钢管对混凝土的约束作用时,试件轴心受压承载力计算值与试验值符合较好;不考虑圆钢管对混凝土约束作用时,试件的轴心受压承载力计算值小于试验值较多。建议计算试件轴心受压承载力应考虑钢管对混凝土的约束作用。

To study the influence of opening ratio of the steel tube wall on the axial compressive behavior of core area of RC beam and concrete filled steel tube composite column joint,quasi-static tests on 18 composite column specimens were conducted.Among the 18 specimens,there were 14 specimens with large openings and 4 specimens without openings on the steel tube wall.Results indicate that the openings have little influence on the axial compressive strength of the specimens when the opening ratio is less than 50%.For the specimens with the opening ratio of 50%,the axial compressive strength increases significantly when the thickness of steel tube wall increases from 8mm to 12mm or 14mm.The axial compressive load-longitudinal strain curves of the specimens drop slowly and the plastic deformation capacity enhances greatly,when the steel tube is strengthened by stiffeners along the perimeter of openings.Taking into consideration of the confinement effect of steel tube on the core concrete,the calculated axial compressive strength of specimens is in good agreement with the test results,but it is much smaller than that of the test results without taking into consideration of the confinement effect of steel tube on the core concrete.Taking into consideration of the confinement effect of steel tube on the core concrete is recommended in the calculation of axial compressive strength of specimens.