采用LUHPC增强塑性铰的预制拼装桥墩抗震性能试验

Seismic Performance Testing on Prefabricated Bridge Columns with LUHPC Reinforced Plastic Hinge

制作了6个桥墩试件,3个现浇和3个预制拼装试件,预制拼装采用课题组提出的"预留灌浆孔"连接方式。通过拟静力试验对LUHPC增强塑性铰桥墩抗震性能开展系统的研究,从损伤发展过程及破坏形态、滞回曲线、骨架曲线、延性、累积耗能、等效刚度等方面对桥墩抗震性能进行系统分析。结果表明:塑性铰区采用LUHPC增强后,能够显著减小桥墩塑性铰区的损伤程度。当LUHPC替换高度为1倍柱宽时,其极限承载力提高了1.5%~3.9%,延性提高了17.1%~32.8%,耗能能力提高了31.6%~43%;当LUHPC替换高度为2倍柱宽时,其极限承载力提高了4.6%~6%,延性提高了24%~58%,耗能能力提高了63%~107.3%;采用LUHPC增强塑性铰的预制拼装桥墩与现浇桥墩具有同等的抗震性能,桥墩塑性铰区采用2倍柱宽的LUHPC替换高度具有更好的抗震性能。

6 column models were made,including 3 cast-in-place columns and 3 precast columns.The assembly adopts the“reserved grouting hole”connection method proposed by the research group.Through the quasi-static testing,the seismic performance of the specimens was systematically analyzed from the aspects of damage development process and failure form,hysteresis curve,envelope,displacement ductility,cumulative energy consumption,equivalent stiffness and so on.The The results show that the replacement of the plastic hinge area with LUHPC can significantly reduce the damage degree of the plastic hinge area of the bridge column.When the replacement height of LUHPC is once of the column width,the ultimate bearing capacity of the precast assembled model is increased by 1.5%~3.9%,the displacement ductility is increased by 17.1%~32.8%,and the energy consumption capacity is increased by 31.6%~43%.When the replacement height of LUHPC is twice of column width,the ultimate bearing capacity of the precast bridge model is increased by 4.6%~6%,displacement ductility is increased by 24%~58%,energy consumption is increased by 63%~107.3%.Precast bridge columns with reserved grouting hole connections have the similar seismic performance as the cast-in-place columns.The plastic hinge zone of the column adopts twice of the column width,the LUHPC replacement height has better seismic performance.