Experimental Research on Shear Capacity of PHC Pipe Pile Strengthened with CFRP
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摘要: 为改善PHC管桩截桩后桩头抗剪承载力不足的情况,分别考虑了内填混凝土芯和外裹碳纤维片材(CFRP)两种加固措施,完成了5个足尺PHC管桩(PHC 400 B 95)试件的抗剪承载力静载试验,获得了试件开裂剪力、极限剪力、破坏形态及桩身应变等数据,分析了不同加固措施对PHC管桩试件抗剪承载性能的增强效果,验证了碳纤维片材加固桩头抗剪承载力公式计算结果的可靠性。研究表明:相比PHC管桩管孔混凝土填芯,外裹碳纤维片材对截桩后桩头抗剪承载力的增强效果更加明显,桩头剪切破坏形态转变为弯曲破坏,改善了桩头延性性能;结合试验数据分析,提出了碳纤维片材加固桩头抗剪承载力公式,其计算结果偏于安全,可用于工程设计。Abstract: In order to improve the insufficient shear capacity of prestressed high strength concrete (PHC) pipe pile head after pile cutting, two reinforcement measures of internal filling concrete core and external wrapping carbon fiber sheet (CFRP) were considered respectively, and the static load test of shear bearing capacity of five full-scale PHC pipe pile specimens (PHC 400 B 95) was completed. The data of cracking shear force, ultimate shear force, failure mode and pile strain deformation were obtained, the enhancement effects of different reinforcement measures on the shear bearing capacity of PHC pipe pile specimens were analyzed, and the reliability of the calculation results of the formula of shear bearing capacity of pile head strengthened with carbon fiber sheet was verified. The results showed that compared with PHC pipe pile with concrete core filling, carbon fiber sheet had better effect on strengthening the shear bearing capacity of pile head after pile cutting, and the shear failure mode of pile head changed to bending failure mode, which delayed the cracking and crushing of pile head concrete and improves the ductility of pile head; according to the analysis of test data, the formula of shear bearing capacity of pile head strengthened with carbon fiber sheet was put forward. The calculation results were safe and reliable, which could be used in engineering design.
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Key words:
- PHC pipe pile /
- carbon fiber reinforced plastics(CFRP) /
- core concrete /
- shear capacity /
- failure mode
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