断丝PCCP管道外贴CFRP修复足尺模型试验研究

断丝是目前预应力钢筒混凝土管(Prestressed Concrete Cylinder Pipe,PCCP)最为常见的一种病害,如不及时加固,极易造成爆管等事故。针对长距离PCCP输水管道难以停水维修问题,提出了一种外贴碳纤维增强复合材料(Carbon Fiber Reinforced Polymer,CFRP)的维修方法。为了探究外贴CFRP修复断丝PCCP效果,采用一根内径2.8m的PCCP管道进行了内水压足尺试验。试验对修复前后PCCP结构应变响应进行了对比分析,结果表明:由于CFRP箍束作用,修复后断丝区中间截面材料应变减小,利于PCCP承压。

CFRP wrapping to retrofit a deteriorated prestressed cylinder concrete pipe: full-scale experiments

The prestressed concrete cylinder pipes (PCCPs) are often deteriorated due to rupture of prestressed steel wires. Such deteriorated PCCPs need to be retrofitted timely and effectively, otherwise they could suffer from explosion. An innovative retrofitting technique is therefore proposed, which is carbon fiber reinforced polymer (CFRP) wrapping outside the deteriorated PCCPs, and the retrofitting technique is especially suitable for the cases that shutting off water is impossible. In order to evaluate the effectiveness of the newly-proposed retrofitting technique for PCCPs, a full-scale PCCP of 2.8 m in inner diameter is tested under internal water pressure. The strains of PCCP structures are compared before and after the repair. It is found that the strains near the ruptured steel wires significantly decrease due to the presence of CFRP, which improves the operation of the PCCPs.