方中空夹层钢管混凝土柱滞回性能研究

Load-displacement hysteretic behavior of concrete filled double skin(CHS inner and SHS outer) steel tubular columns

以轴压比和空心率为主要参数,进行了12个方中空夹层钢管混凝土试件和4个方实心钢管混凝土试件滞回性能的试验研究。试验表明:方中空夹层钢管混凝土和方实心钢管混凝土荷载-位移滞回曲线饱满,其延性明显优于空钢管试件;轴压比越大的试件,初始刚度越大,但刚度后期退化越快。比较了国内外较典型的几种设计规范(程)对试件抗弯刚度的计算,结果表明,AISC-LRFD(1999)、EC4(1994)、BS5400(1979)、DBJ 13-51(2003)的计算结果与实测的初始抗弯刚度较吻合,DBJ 13-51(2003)的计算结果与实测的使用阶段抗弯刚度最接近。在确定了钢材和混凝土的本构关系的基础上,采用数值方法对荷载-位移滞回曲线进行了计算,理论计算结果与试验结果较吻合。最后分析了轴压比、空心率、长细比、名义含钢率、材料强度等参数对荷载-位移骨架曲线的影响。

The flexuml force-deformation behavior of 12 concrete filled double skin steel tubular（CFDSST） columns with circular hollow section（CHS） inner and square hollow section（SHS） outer and four concrete filled steel tubular（CFST） columns were studied and the results are presented in this paper. The parameters are the axial compression ratio and hollow section ratio. Test results show that the hysteretic curves of the columns are good. The CFDSST columns and the CFST columns have significant increase in ductility of the outer jacket. With the increasing of axial load level, the initial flexural stiffness increases, but the flexural stiffness degrades rapidly. Comparisons are made with flexural stiffness predicted by the existing codes for CFDSST columns. Results show that, AISC-LRFD（1999） ,EC4（1994） ,BS5400（ 1979）, DBJ 13-51 （2003） methods are in good agreement with the tested initial section flexural stiffness, and DBJ 13-51（2003） method predicts best with the tested serviceability-level section flexural stiffness. A mechanics model is developed in this paper for CFDSST columns with CHS inner and SHS outer. The curves of lateral load （P） versus lateral displacement （△） of CFDSST are in agreement with test results. Parametric analysis are performed on the behaviors of lateral load versus lateral displacement relationship for the composite columns, the parameters include： the axial compression level, hollow section ratio, slenderness ratio, nominal steel ratio, strength of the materials, etc.