波纹管-UHPC槽组合连接预制拼装桥墩抗震性能研究

INVESTIGATION ON SEISMIC PERFORMANCE OF PRECAST PIERS WITH COMBINED CORRUGATED PIPE-UHPC SLOT CONNECTION

  • 摘要: 为推动装配式桥墩在高抗震设防区的发展,该文设计了基于波纹管与高性能混凝土(UHPC)槽的新型节点连接构造,加工了1个现浇桥墩-盖梁节点(CIP)和1个基于波纹管-UHPC槽的桥墩-盖梁连接节点(CP-USCP),并完成了拟静力加载试验。试验结果表明:试件破坏模式均为延性破坏,CP-USCP桥墩呈现与CIP桥墩相近的承载力、耗能能力及位移延性,大纵漂率(6%)下CP-USCP桥墩承载力能够保持在峰值荷载的88%以上。通过数值模拟分析,探究了纵筋强度、配筋率及内部补偿钢筋搭接长度对CP-USCP桥墩抗震性能的影响,表明随着纵筋强度提高,塑性铰区范围略有减小;补偿钢筋搭接长度为350 mm~750 mm时,墩柱塑性铰区存在截面刚度突变,导致塑性铰发生上移;当搭接长度增加为800 mm~1000 mm时,塑性铰位于墩底。根据试验及模拟结果提出内部补偿钢筋所需的搭接长度公式。

     

    Abstract: To promote the development of precast piers in high seismic fortification areas, this paper proposed a novel joint with a connection configuration based on corrugated pipe and ultra-high performance concrete (UHPC) slot, designed the cast-in-place (CIP) joint and the joint with a corrugated pipe-UHPC slot connection pier (CP-USCP), and conducted pseudo-static tests. The experimental results show a ductile damage mode of the specimens. Moreover, the CP-USCP piers exhibit a bearing capacity of over 88% of the peak load at a large drift ratio (6%). Through numerical simulation analysis, the effects of longitudinal reinforcement strength, reinforcement ratio and the lap length of internal compensating reinforcement on the seismic performance of CP-USCP piers were discussed, respectively. The results indicate that the range of plastic hinge area decreases slightly with the increase of longitudinal reinforcement strength. A sudden change in the cross-sectional stiffness within the plastic hinge area of the pier occurs at a compensation lap length of 350 mm~750 mm, leading to an upward shift of the plastic hinge. When the lap length is increased to 800 mm~1000 mm, the plastic hinge is located at the bottom of the pier. Based on the test and simulation results, a formula for the required lap length of the internal compensation reinforcement is proposed.

     

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