方钢管再生混凝土柱抗震性能试验研究

为研究方钢管再生混凝土柱的抗震性能，设计并制作了6个试件，对其进行拟静力试验。考虑再生粗骨料取代率和轴压比2个变化参数，观察试件受力的全过程和破坏形态，分析试件的滞回曲线、骨架曲线、延性、耗能性能和刚度退化等，并采用相关规程计算低周反复荷载作用下方钢管再生混凝土柱的压弯承载力。试验研究和计算结果表明：试件破坏过程以及破坏形态均与普通钢管混凝土柱试件相似，主要表现为试件根部钢管的鼓曲破坏；试件的滞回曲线比较饱满，滞回曲线的形状从梭形发展到弓形；在试验选取的再生粗骨料取代率参数范围内，试件的滞回曲线受其影响不大；试件的平均位移延性系数接近3；破坏时等效黏滞阻尼系数介于0.323~0.360之间；建议对采用规程GJB 4142-2000计算的反复荷载作用下方钢管再生混凝土柱的压弯承载力乘以0.92的折减系数；对采用规程DBJ 13.51-2003计算的反复荷载作用下方钢管再生混凝土柱的压弯承载力乘以1.13的扩大系数。

Experimental study on seismic behavior of recycled aggregateconcrete filled square steel tube columns

To study the seismic behavior of recycled aggregate concrete filled steel tubular (RACFST) columns, six specimens with different replacement rates of recycled coarse aggregate and axial compression ratios were tested under the cyclic reversed loading. The entire loading process and failure mode were observed, the hysteretic curve, skeleton curve, ductility, dissipation capacity and stiffness degradation were analyzed, and then the ultimate compression and flexural capacities under cyclic reversed loading were calculated using existing theories. It is shown that the failure process and failure mode of RACFST columns are similar to those of concrete filled steel tubular columns, in which the circular steel tube at the bottom is buckled. All the hysteretic curves which change from bow shape to arch shape are plump, and within the parameters selected in test, the influence of replacement rate on hysteretic curves is little. The average displacement ductility factor is close to 3.0. The equivalent viscous damping coefficients at failure point are between 0.323 and 0.360. It is suggested that design formulas with the consideration of a reduction factor 0.92 and an amplification factor 1.13 in GJB 4142-2000 and DBJ 13-51-2003 respectively can be used to design the compression and flexure strength of RACFST columns under cyclic reversed loading.