震损RC柱FRP加固后抗震性能数值模拟分析

NUMERICAL SIMULATION OF SEISMIC BEHAVIOR OF EARTHQUAKE DAMAGED RC COLUMNS STRENGTHENED WITH FRP

使用有限元软件ABAQUS,基于箍筋约束混凝土、钢筋以及FRP材料的材料本构模型,完成了未震损未加固、未震损FRP加固和震损后FRP加固的RC柱抗震数值模拟分析。对震损后FRP加固的RC柱,完成不同程度震损模拟;使用生死单元法实现严重震损混凝土的剔除与替换以及FRP的加固;再模拟修复加固后RC柱的加载,模拟结果与试验结果基本吻合。对比了3种RC柱抗震性能的数值模拟结果,发现严重震损后用FRP加固的RC柱其抗侧刚度与承载力不能完全恢复,需要考虑不同损伤程度与不同FRP加固措施等对加固效果的影响。研究了不同损伤程度和加固方法下的RC柱,结果表明:对于中等震损的试件,纵横向FRP组合加固可以完全恢复并超越原有抗震性能;对严重损伤RC柱,外围损伤严重混凝土的修复与替换是影响震损RC柱加固后性能的关键;相较于仅有横向GFRP环向加固,纵横向FRP组合加固的效果更好。

Based on appropriate constitutive models of materials,undamaged and un-strengthened,undamaged but FRP strengthened,and FRP strengthened pre-damaged RC columns are numerically simulated and analyzed by ABAQUS.The reasonable pre-damage simulation method is proposed,and the model change interaction method is adopted to simulate the demolishment and replacement of severely damaged concrete and FRP strengthening.Numerical simulation results are basically consistent with the experimental results.On this basis,the numerical simulation results of three kinds of RC columns are compared.It is found that:the lateral stiffness and bearing capacity of FRP strengthened severely damaged RC columns cannot be fully restored,and the effects of different damage degrees and different FRP strengthening measurements need to be considered.RC columns with different damage degrees and strengthening methods are studied.The results show that the longitudinal and transverse FRP composite reinforcement is effective for the specimens with moderate seismic damage.The repair and replacement of severely damaged peripheral concrete is the key to the performance of FRP strengthened predamaged RC columns.Compared with transverse FRP strengthening,the effect of longitudinal and transverse FRP combination reinforcement is better.