冻融循环后圆钢管混凝土短柱轴压性能试验研究

Experimental research on axial compression behavior of circular CFST short columns after freeze-thaw cycles

对冻融循环作用后圆钢管混凝土短柱的受力性能进行试验研究,以钢管壁厚、冻融循环作用次数以及混凝土强度等级为设计参数。试验中分析了冻融循环作用后圆钢管混凝土短柱的轴压破坏现象、荷载-位移曲线以及应力-应变曲线等。试验结果表明:经冻融循环作用后的圆钢管混凝土短柱的轴压破坏形态与相应未经冻融循环作用短柱类似;减小圆钢管混凝土短柱的径厚比可提高其在冻融环境下的轴压承载力;提高混凝土强度等级能增加圆钢管混凝土短柱的初始刚度;冻融循环对圆钢管混凝土短柱的轴压承载力影响较小;预测圆钢管混凝土可适用于遭受冻融作用的地区。根据试验结果,提出了圆钢管混凝土经冻融循环后的轴压承载力计算公式,计算结果与试验结果吻合较好。

Experimental study on mechanical properties of circular CFST stub columns after freeze-thaw cycles,the parameters of the test were the thickness of circular steel tubular,the number of freeze-thaw cycles and the strength of concrete. The axial compression failure phenomenon,load-displacement curve and stress-strain curve of the circular CFST stub column after freeze-thaw cycles were analyzed. The experimental results show that the failure mode of the circular CFST short column under axial compression after freeze-thaw cycles is similar to that without freeze-thaw cycle;the axial bearing capacity of circular CFST stub columns after freeze-thaw cycles is improved with the decreasing ratio of radial diameter to thickness of specimens;the initial stiffness of the circular CFST stub columns increases with the increasing concrete strength grade;the freeze-thaw cycles have a little effects on the axial bearing capacity of circular CFST stub columns;the circular CFST short columns have better application in freezing and thawing environment. According to the test results,the formula for caculating the axial bearing capacity of circular CFST stub column after freeze-thaw cycles was proposed,which was in good agreement with the experimental results.