装配式内置钢管混凝土异形柱框架L形节点斜向加载抗震性能试验研究

Seismic behavior of L-shaped joints of prefabricated concrete-filled steel tubular frame with special-shaped columns under oblique loading

为研究装配式内置钢管混凝土异形柱框架节点的抗震性能,设计了3个足尺节点,变化参数为轴压比,通过斜向低周往复加载试验,分析其滞回性能、变形能力、耗能能力和刚度退化,结果表明:装配式内置钢管混凝土异形柱框架L形节点在斜向加载时破坏形式为梁端塑性铰破坏,满足“强柱弱梁”设计要求;试验滞回曲线饱满,当轴压比由0.2增加到0.4时,开裂、屈服和峰值荷载均增大,发生破坏时的层间位移角平均值为1/34。在轴压比0.2~0.4范围内,位移延性系数均大于1.0,等效黏滞阻尼系数均大于0.2,且随着轴压比增大两者变化均较小,达到破坏时的割线刚度平均值约为初始刚度的38.3%,节点具有较好的耗能和变形能力。

In order to study the seismic performance of prefabricated concrete-filled steel tubular special-shaped column frame joints,three full-size L-shaped joints with concrete-filled steel tubular special-shaped columns were designed.The variable parameter was the axial compression ratio.Through the oblique low-cycle reciprocating loading test,the hysteretic performance,deformation capacity,energy dissipation capacity,and stiffness degradation of specimens were analyzed.The results show that the failure mode of the L-shaped joints of the frame with prefabricated concrete-filled steel tubular special-shaped columns under oblique loading is plastic hinge failure at the beam end,which meets the design requirements of‘strong column and weak beam’.The hysteretic curve of the specimen is full.When the axial compression ratio increases from 0.2 to 0.4,the cracking,yield,and peak loads of the specimen increase,and the average value of the interlayer displacement angle when the failure occurs is 1/34.When the axial compression ratio is within the range of 0.2 to 0.4,the displacement ductility coefficient of specimens is greater than 1.0,and the equivalent viscous damping coefficient is greater than 0.2.The change in the aforementioned two indicators is minimal with the increase of the axial compression ratio,and the average value of the secant stiffness at the time of failure is about 38.3%of the initial stiffness,and the specimens show good energy dissipation and deformation capacities.