矩形中空夹层再生混凝土钢管短柱轴压试验研究

以截面形式、截面长宽比和混凝土类型为参数共设计了8根矩形中空夹层钢管混凝土试件,对其进行轴压实验并对其破坏形态、荷载-纵向应变关系曲线及外钢管横向应变发展规律进行分析。其中截面形式包括矩形套矩形和矩形套圆形两种,截面长宽比分别为1.25和1.5,混凝土类型包括普通混凝土和再生混凝土(再生粗骨料取代率为50%)两类。结果表明:对于截面形式相同的试件,长宽比较大者极限承载力更小,且其长边横向应变发展更快;对于长宽比相同的试件,矩形套矩形截面的试件长边横向应变发展比矩形套圆形截面的更快;混凝土类型对试件的极限承载力和破坏形态影响不大。最后运用有限元软件ABAQUS对8根短柱的轴压全过程进行模拟,并将有限元计算得到荷载-纵向应变曲线与实验实测曲线进行对比,两者吻合较好且互相验证。

Experimental Investigation on Axial Compression of Rectangular Recycled Concrete-Filled Double-Skin Steel Tube Short Column

Taking cross section form, section length-width ratio and concrete type as parameters, 8 rectangular concrete-filled double-skin steel tube specimens were designed. Axial compression experiment was carried out to study their failure mode, load-longitudinal strain curve and lateral strain development of outer steel tube. The cross section form includes 2 kinds, namely, both outer and internal rectangular casing tube and rectangular outer and circular internal casing tube, respectively; the cross section length-width ratio is 1.25 and 1.5, respectively; concrete type includes 2 kinds, namely, common concrete and recycled concrete with 50% recycled coarse aggregate substitution rate, respectively. Experimental results show that for specimens with same cross section, the ultimate bearing capacity of specimens with larger length-width ratio is smaller, and its lateral strain development is faster; for specimens with same length-width ratio, the lateral strain development of both outer and internal rectangular casing tube is faster than that of rectangular outer and circular internal casing tube; the influence of concrete type on specimen's ultimate bearing capacity and failure mode is not obvious. Finally, numerical simulation of 8 short columns axial compression process was carried out based on ABAQUS finite element method. The comparison between calculated load-longitudinal strain curve and experimentally obtained curve indicates that both curves are in good agreement and can be mutual authentication.