PVA-ECC加固桥墩抗震性能试验研究

Experimental study on the seismic behavior of bridge piers strengthened with PVA-ECC

为增强现役桥墩的抗震能力,研究基于聚乙烯醇纤维增强水泥基复合材料(PVA-ECC)的桥墩抗震加固性能,完成了5个剪跨比为4.2的圆形桥墩试件拟静力试验。通过试件的破坏形态与抗震性能指标,分析了PVA-ECC加固桥墩抗震性能,讨论了轴压比与PVA纤维体积掺量对桥墩抗震性能的影响。试验结果表明:采用PVA-ECC材料可以明显改善桥墩的破坏形态,控制裂缝的宽度和发展,提高桥墩的损伤容限与承载能力,表现出良好的延性和耗能能力;随轴压比增大,PVA-ECC加固桥墩的承载力提高,位移延性系数与耗能能力明显降低;随PVA纤维体积掺量增大,PVA-ECC加固桥墩的滞回曲线更加饱满,有效提升了桥墩的延性与耗能能力。

In order to improve the seismic capacity of bridge piers in service period,the seismic performances of bridge piers strengthened with polyvinyl alcohol-engineered cementitious composite(PVA-ECC)were investigated.Five circular pier specimens with a shear span ratio of 4.2 were tested by quasi-static tests.Based on the failure modes and seismic performance indicators,the seismic performances of specimens strengthened with PVA-ECC were analyzed.Furthermore,the influences of both axial compression ratio and PVA fiber volume content on the seismic performances of piers were discussed.The experimental results show that PVA-ECC obviously improves the failure modes and controls the width and development of crack.This material also enhances the damage tolerance and bearing capacity of bridge piers.Therefore,the piers perform good ductility and energy dissipation capacity.With the increase of axial compression ratio,the bearing capacity of piers strengthened with PVA-ECC is increased.However,the displacement ductility coefficient and energy dissipation capacity are obviously reduced.With the increase of PVA fiber volume content,the hysteretic curve of piers strengthened with PVA-ECC is fuller.It effectively improves the ductility and energy dissipation capacity of bridge piers.