方钢管再生混凝土长柱轴心受压性能试验研究

Experimental research on recycled aggregate concrete-filled square steel tubular long columns under axial compression

以长细比为主要变化参数,对8个方钢管再生混凝土长柱试件进行了轴心受压单调加载试验。通过试验,观察了试件受力全过程和破坏形态,得到了荷载-位移曲线和荷载-应变曲线,分析了长细比对试件承载性能的影响,并讨论了国内现行常见规范所推荐方法对方钢管再生混凝土长柱轴压承载力计算的适用性。结果表明:方钢管再生混凝土长柱轴心受压主要经历了弹性、屈服以及破坏三个阶段,长细比较小试件,主要体现为材料强度破坏,长细比较大的试件,受二阶效应影响明显,主要表现为整体弯曲失稳破坏,所有试件破坏前均出现了管壁局部屈曲现象;长细比对试件承载力影响较大,试件承载力随长细比的增加而逐渐降低;建议采用DBJ 13-51-2003与CECS 159:2004规范进行方钢管再生混凝土轴压长柱的承载力计算。研究结果可为工程应用提供参考。

Considering slenderness ratio as main factors, the tests on 8 recycled aggregate concrete-filled square steel tubular long columns under axial compression were carried out.Through the test, the whole loading process and failure mode were observed, the load-displacement curves and load-strain curves were also captured. The influence of slenderness ratio on the bearing capacity was analyzed.And the applicability of calculation methods recommended by current standards to the specimens were discussed.The results show that the specimens under axial compression mainly experience three stages,e lastic stage,y ield stage and failure stage. Specimens with smaller slenderness ratio are behaving mostly as the intensity failure,while the ones with relatively large slenderness ratio are behaving mostly as the overall bending instability failure,because they are significantly affected by the second-order effects.The local-buckling of the steel tube have appeared at all specimens before failure.Slenderness ratio has great effect on the bearing capacity of specimens.When the slenderness ratio increases, the bearing capacity will decrease.The technical specification DBJ13-51-2003 and CECS159：2004 are recommended for calculating the bearing capacity of recycled aggregate concrete-filled square steel tubular long columns under axial compression.The results can be useful reference to engineering application.