圆钢管自应力钢渣增强混凝土柱的受力机制及承载力计算

Mechanical behavior and bearing capacity calculation of self-stressing steel slag aggregate reinforced concrete filled circular steel tube columns

为研究圆钢管自应力钢渣增强混凝土(钢渣/混凝土@圆钢管)柱的受力机制,设计了8根钢渣/混凝土@圆钢管柱进行轴心受压加载试验,其中短柱试件6个,中长柱试件2个。试验考虑钢渣/混凝土膨胀率、径厚比和长径比共3个变化参数。观察试件的受力破坏全过程,获取应力-应变曲线、峰值应力等重要参数,分析各变化参数对钢渣/混凝土@圆钢管轴压柱受力性能的影响。结果表明:钢渣/混凝土@圆钢管轴压短柱的破坏形态表现为中部鼓曲状剪压破坏,而钢渣/混凝土@圆钢管轴压中长柱则呈弯曲屈曲破坏;各试件受力破坏全过程曲线均经历峰值点、下降段、缓慢上升段等历程,与普通钢渣/混凝土相比,各试件的峰值应变和峰值应力明显提高,且钢渣/混凝土@圆钢管轴压短柱试件较钢渣/混凝土@圆钢管轴压中长柱试件提高更为显著。根据极限平衡条件和全过程分析,提出钢渣/混凝土@圆钢管柱承载力计算公式。在试验研究基础上,建立钢渣/混凝土@圆钢管柱的应力-应变关系模型,理论计算结果与试验实测数据吻合较好。研究成果可为钢渣/混凝土@圆钢管柱的进一步研究和工程应用提供参考。

To study the mechanical mechanism of self-stressing steel slag aggregate reinforced concrete filled circular steel tube(steel slag aggregate/concrete@circular steel tube) columns, eight specimens including six short columns and two intermediate length columns were designed for axial compression test, the variable parameters, such as the diameter-thickness ratio, expansion rate of steel slag aggregate concrete and length-diameter ratio were considered.The whole failure process of specimens was observed, and then the strain-stress curves as well as the peak stress was obtained. The influence of variable parameters on the mechanical behavior of self-stressing steel slag aggregate/concrete@circular steel tube columns was analyzed. Test results indicate that the short columns under axial load exhibit shear failure while the intermediate length columns experience global flexural buckling failure mode. The stress-strain curves of all specimens are basically similar, which undergo the peak point, descending section, slow rise section and so on. The peak strain and peak stress of all specimens are significantly increased compared with those of common steel slag aggregate concrete, and the improvement effects are more obvious in short columns than those in intermediate length columns. According to the limit equilibrium condition and entire process analysis, the calculation formula of bearing capacity of self-stressing steel slag aggregate/concrete@circular steel tube columns was proposed, and then the stress-strain model of self-stressing steel slag aggregate/concrete@circular steel tube columns was established depending on the experimental data. The theoretical calculation results are in good agreement with test data. The research results can provide reference for further research and engineering application of self-stressing steel slag aggregate/concrete@circular steel tube columns.