PVA-ECC加固桥墩抗震性能试验与数值研究

为了全面研究工程水泥基复合材料（ECC）加固桥墩的抗震性能，对采用聚乙烯醇纤维增强水泥基复合材料（PVA-ECC）加固的桥墩进行了拟静力试验。并基于有限元分析软件OpenSees建立了数值模型，通过对比数值模拟结果与试验结果，验证有限元分析的有效性，在此基础上对PVA-ECC加固桥墩进行数值参数分析，探讨轴压比、新旧材料厚径比及体积配箍率变化对桥墩抗震性能的影响规律。结果表明:数值模拟的滞回曲线与骨架曲线和试验基本吻合；与普通混凝土桥墩相比，新旧材料厚径比为0.10时，即可获得优异的延性性能，ECC加固的桥墩变形性能显著提升，极限位移提高，滞回曲线更加饱满，抗震性能更加优异。对于高轴压比情况，为了确保ECC加固桥墩的延性性能，应根据实际情况增加新旧材料厚径比；ECC材料可部分替代箍筋作用，适用于箍筋配置不足的桥墩加固，PVA-ECC具有较好的工程抗震加固的作用。

Numerical analysis on the seismic behavior of bridge piers reinforced by PVA-ECC

To comprehensively investigate the seismic behavior of piers reinforced by engineered cementitious composite (ECC), pseudo static tests of piers reinforced by polyvinyl alcohol-engineered cementitious composite (PVA-ECC) was carried out, and numerical simulation was performed by using OpenSees. The validity of the finite element analysis was verified by comparing the numerical simulation results with the test results. The numerical parameter analysis of piers reinforced by PVA-ECC was carried out to discuss the effects of axial compression ratio, thickness ratio of old and new materials and volume-stirrup ratio on the seismic behavior of piers. The results indicate that:The hysteretic curve and the skeleton curve of numerical simulation were in good agreement with those from the experiment. Compared with the normal concrete pier, thickness to diameter ratio of old and new materials only needs to be 0.1 to obtain excellent ductility performance. The deformation performance of piers reinforced by ECC were significantly improved, the limit displacement was improved, the hysteresis curve was fuller, and the seismic behavior were better. For the case of high axial compression ratio, to ensure the ductility of piers reinforced by ECC, thickness to diameter ratio of old and new materials should be increased according to the actual situation. ECC can partially replace the role of stirrup, suitable for piers reinforcement with insufficient stirrup configuration. The PVA-ECC has better function of engineering seismic reinforcement.