双层矩形钢管-轻质混凝土短柱轴压性能

Axial compression behavior of double-layer rectangular steel tube-lightweight concrete short columns

为了提高冷弯薄壁型钢-轻质混凝土组合剪力墙中端柱的轴压承载力,提出双层矩形钢管-轻质混凝土组合柱。对不同构造形式的6个短柱进行轴压试验,研究截面尺寸和高宽比对短柱破坏模式、荷载-位移曲线和极限承载力的影响,分析内、外钢管应变发展规律。结果表明:不同截面尺寸和高宽比短柱的破坏模式不同;随着截面尺寸的增大,试件的破坏模式由外钢管端部的局部屈曲转为外钢管端部屈曲和中下部鼓曲;随着高宽比的增大,试件外钢管顶端屈曲程度增大;内部破坏特征为内钢管的局部鼓曲和轻质混凝土的剪压破坏;试件极限承载力随截面尺寸的增大而提高,随高宽比的增大而降低。基于以上结果,建立了该新型组合短柱的轴压承载力计算公式。

In order to improve the axial bearing capacity of the end columns in the cold-formed thin-walled steel-lightweight concrete composite shear wall,a double-layer rectangular steel tube-light concrete composite column was proposed.A total of 6 short columns with different structural forms were tested.The effects of the section size and aspect ratio of short columns on the failure mode,load-displacement curve and ultimate bearing capacity were investigated.Then the development of the strain of steel tube was analyzed.Results indicate that the failure modes of short columns with different section sizes and aspect ratios are different.With the increase of the section sizes,the failure modes change from end-buckling of the outer steel tube to end-buckling and bulging at the middle height of the outer steel tube.The local buckling at the top of the outer steel tube increases with the increase of the aspect ratios.The internal failures are characterized by the local buckling of the inner steel tube and the shear-compression failure of lightweight concrete.The ultimate bearing capacity of the column increases with the increase of section size,but it decreases with the increase of aspect ratio.Finally,based on the above analysis,the axial bearing capacity formula of the composite column is established.