高轴压比CFRP约束钢筋混凝土圆柱抗震性能试验与有限元分析

摘要

To investigate the seismic behavior of FRP-confined circular RC columns with high axial compression ratio, six columns confined with Carbon Fiber-Reinforced Polymer （CFRP） at plastic hinge region and two control columns were tested under constant axial load and cyclic lateral force. Test results demonstrated marked improvement in the ductility and energy dissipation of the columns due to CFRP wrapping in the plastic hinge region and the contribution of hoops to the confining effect should not be ignored under the condition of high axial compression ratio. A nonlinear analytical procedure was developed using fiber model method based on OpenSees （Open System for Earthquake Engineering Simulation）. The simulation results agree well with the experimental results for axial compression ratios less than O. 45. Inclusion of the confining effects of both the hoop~ and CFRP results in better simulation of the test results if the .axial compression ratio exceeds 0.45. Finally, influences of axial compression ratio and length of CFRP in the plastic hinge region on the seismic performance of FRP-confined columns were analyzed. The results indicate that the lateral loading capacity of columns begins to decrease when axial compression in the plastic hinge region exceeds 1.2 times the column diameter, the wrapped columns. ratio exceeds 0.6. If the length of wrapped CFRP performance could be equivalent to that with fully%为研究高轴压比下FRP约束钢筋混凝土圆柱的抗震性能，对6根碳纤维约束钢筋混凝土圆柱及2根对比柱进行伪静力试验。结果表明：塑性铰区包裹碳纤维可显著改善高轴压比柱的抗震性能，轴压比较高时不应忽略箍筋对核心混凝土的约束贡献。基于OpenSees中的纤维模型，对柱水平力．位移滞回曲线进行有限元模拟。轴压比小于0．45时，数值模拟与试验结果吻合较好；轴压比大于0．45时，考虑核心混凝土受箍筋及FRP双重约束的计算结果与试验结果更为接近。分析轴压比、FRP包裹长度等参数对约束柱抗震性能的影响，轴压比大于0．6时，FRP约束混凝土圆柱的水平承载力开始降低；FRP在塑性铰区的包裹长度为1．2倍柱直径时，可达到与全柱包裹相当的效果。