方钢管再生混凝土短柱的轴压力学性能试验

Experiment on mechanical behavior of recycled aggregate concrete-filled square steel tubular short columns under axial compression

为研究钢管宽厚比及再生骨料取代率对方钢管再生混凝土短柱力学性能的影响,设计9根方钢管再生混凝土短柱进行了轴压试验,观察了试件在轴压力作用下的破坏过程,分析了钢管宽厚比和再生骨料取代率对试件荷载—位移和荷载—应变曲线的影响。结果表明,宽厚比及再生骨料取代率对钢管再生混凝土短柱的最终破坏形态影响不大,与普通钢管混凝土短柱相似,各试件均呈剪切破坏,最终破坏时,其纵向变形均超过30 mm;随着再生骨料取代率增大,荷载—位移曲线下降段越陡,但随着钢管宽厚比的增大,再生骨料取代率超过30%后,试件极限承载力越接近,说明考虑再生骨料取代率的不利影响更合理。最后结合试验提出了钢管再生混凝土短柱承载力计算方法,将计算结果与相关规程进行了对比,供工程应用参考。

In order to research the influence of the width / thickness ratio of steel tube and the replacement ratio of recycled aggregate in core concrete on the mechanical behavior of recycled aggregate concrete-filled square steel tube（ RACFSST） short columns,9 specimens with different parameters were designed and tested under axial compression. The failure process of specimens was observed,and the impact of the width / thickness ratio of steel tube and the replacement ratio of recycled aggregate in core concrete on the loading-longitudinal displacement curves and loading-strain curves of specimens was analyzed. The results showed that the width / thickness ratio and the re-placement ratio of recycled aggregate have little effect on the failure patterns of RACFSST short columns,which were similar to the situation of the ordinary concrete-filled steel tube short columns,and the failure pattern of the specimens was shear failure. Its vertical deformation was more than30 mm eventually. As the replacement ratio of recycled aggregate decreased,the descent stage of load-displacement curves became steeper,but the bearing capacity of the RACFSST short columns was closer to one another with the increase of width / thickness ratio after the replacement ratio of recycled aggregate was over 30%,which indicated that taking the negative influence of replacement ratio of recycled aggregate into account would be more reasonable. Based on the tests,the bearing capacity calculation method of the RACFSST short column is proposed,which could provide practical project with useful reference.