PCCP管内环向预应力碳纤维板加固数值分析

Numerical analysis of reinforcement with circumferential prestressed carbon fiber board in PCCP pipe

  • 摘要: 为充分发挥碳纤维板(CFRP)的抗拉性能,提升断丝预应力钢筒混凝土管(PCCP)的承载能力,提出了管内环向预应力碳纤维板加固方法。研究分析CFRP和混凝土的环向应力,得出拉梅公式的力学模型计算结果与有限元计算结果基本相符,两者结果最大仅相差9.3%。PCCP钢丝断丝率相同情况下,对不同断丝分布进行了计算研究,断丝率相同情况下断丝在同一位置时最不利。断丝发生时,在断丝处从管内到管外的混凝土损伤由小变大。重点对断丝率为10%时预应力CFRP加固前后性能进行了比较。结果表明:正常工作水压下,断丝处PCCP混凝土、钢筒的应力应变显著减小,说明CFRP起到了很好的加固效果;断丝率越高,在混凝土内壁没有损坏前,CFRP的作用越大。管内环向预应力碳纤维板加固方法还具有施工周期短、环境影响小、非开挖、易操作的特点,对实际PCCP应急修复具有很好的参考价值。

     

    Abstract: In order to give full play to the tensile properties of carbon fiber boards (CFRP), and improve the load-bearing capacity of prestressed concrete cylinder pipe (PCCP), a method of reinforcement with circumferential prestressed carbon fiber board in PCCP was proposed. By comparing the mechanical model calculation results of Lame’s formula with the finite element calculation results, it is concluded that the two results are basically in agreement. The maximum difference is only 9.3%. The cases of the same total wire broken rate with different broken distribution were calculated and studied, and it is found that the worst case is that the broken wires are at the same position. When wires break, the concrete damage index near broken wires increases from inside to outside. The reinforcement effect of PCCP with 10% of wire breakage rate was studied. When the wire breakage rate was 10%, the stress and strain of concrete and steel cylinder at the broken wires were significantly reduced under normal working water pressure, which indicates that CFRP has a very good reinforcement effect. The higher the wire breakage rate, the better the effect of CFRP before the concrete inner wall is damaged. This method also has the characteristics of short construction period, non-excavation, and easy operation, and has a good reference for actual PCCP emergency repair.

     

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