环向均匀脱空对圆钢管超高强混凝土柱偏压受力性能的影响

为研究环向均匀脱空对圆钢管超高强混凝土柱偏压受力性能的影响,通过环向均匀脱空圆钢管超高强混凝土柱的偏压试验,研究环向均匀脱空圆钢管超高强混凝土柱的承载能力、延性和破坏模式.结果表明:随着偏心率的减小,钢管局部屈曲的发生时刻提前,试件的延性减小;环向均匀脱空试件的初始刚度与无脱空试件的初始刚度基本相同;混凝土压溃位置与钢管局部屈曲位置基本一致,压溃程度随偏心率的减小而增大,与无脱空试件相比,环向均匀脱空试件的混凝土破碎更加严重;偏压试件的受拉裂缝近似沿中截面对称分布,裂缝长度和宽度随偏心率的减小而减小;无脱空和环向均匀脱空对圆钢管超高强混凝土柱承载力计算公式与实测结果吻合良好.

Effect of Circumferential Uniform Gap on Eccentric Compressive Behavior of Circular Concrete-Filled Steel Ultra-High-Strength Tube Columns

In order to investigate the effect of circumferential uniform gap on the eccentric compression behavior of circular ultra-high-strength concrete-filled steel tube columns, through the eccentric compression test of circular ultra-high-strength concrete-filled steel tube columns with circumferential uniform gap, the bearing capacity, ductility and failure mode of circular ultra-high-strength concrete-filled steel tube columns with circumferential uniform gap are studied. The results show that, as the eccentricity ratioes decrease, the happening time of local buckling of the steel tube is advanced, and the ductility of the specimen decreases. The initial stiffness of the specimens with circumferential uniform gap is basically the same as that of the specimens without gap. The crushing regions of concrete are basically consistent with the local buckling regions of steel tube, and the degree of crushing increases with the decrease of the eccentricity ratio; compared with the specimens without gap, the concrete of the specimens with circumferential uniform gap is more seriously broken. Tensile cracks of the specimens under eccentric compression are distributed symmetrically along the middle section, and the crack length and width decrease with the decrease of the eccentricity ratio. The results of formula calculating the bearing capacity of circular ultra-high-strength concrete-filled steel tube columns without gap and with circumferential uniform gap agree well with the measured results.