轴压比对SRHC柱-RC梁框架边节点抗震性能试验研究

Experimental Study on the Effect of Axial Compression Ratio on the Aseismic Behavior of SRHC Column and RC Beam Frame Side Joints

为研究轴压比对型钢超高强混凝土柱-钢筋混凝土梁(SRHC柱-RC梁)框架边节点抗震性能影响,通过对3个试件进行拟静力加载试验,得到了试件在低周反复荷载作用下的破坏形态、滞回曲线、骨架曲线、延性性能及耗能能力。试验结果表明轴压比对试件的破坏形态有着显著的影响,轴压比为0.25时,试件发生延性较好的梁端塑性铰区破坏;轴压比为0.38时,试件发生节点核心区剪切破坏并伴随梁端形成塑性铰;轴压比为0.45时,试件破坏过程明显缩短,发生典型的节点核心区脆性破坏;试验轴压比为0.25时,试件的滞回环饱满程度较为理想,骨架曲线下降段较平缓,轴压比提高到0.38时,位移延性系数降低幅度高达53%,同时等效黏滞阻尼系数也相应的降低了20%左右,说明试验轴压比越大,试件的延性性能越弱,抗震耗能能力越差。

In order to study the effect of axial compression ratio on the seismic behavior of frame side joints of the steel reinforced high-strength concrete （SRHC） column and reinforced concrete （RC） beam, static loading tests were conduct- ed on 3 joint specimens, through which the failure patterns, hysteretic curve, frame curve, ductility and energy dissipa- tion of the specimens under low-cycle repetitive loading were obtained. The results showed that, the axial compression ra- tio had a significant impact on the failure patterns of the specimens, when the axial compression ratio reached 0.25 the plastic hinge failure occurred at the beam ends with better ductility; when the ratio reached 0.38, shear failure occurred at the core section of the joints along with the plastic hinge failure at the beam ends; when the ratio reached 0.45, the failure process shortened significantly, and shear failure occurred at the core section of the joints. It is found that when the ratio was 0.25, the hysteretic loop presented an ideal full curve, the frame curve descended gently; while when the ratio was 0.38, the displacement ductility coefficient decreased 53 %, and the equivalent viscous damping coefficient de- creased 20%. These results indicate that the higher the axial compressive ratio the weaker the ductility and therefore the worse the aseismic energy dissipation of the specimens.