Effect of Wire Breaks on Prestressed Concrete Cylinder Pipe (PCCP) Reinforced with Steel Liners—A Case Study

The structural integrity of Prestressed Concrete Cylinder Pipe (PCCP) will be weakened if the breakage of prestressing wire occurs. Because the prestressing wire is the principal component of the pipe, as the prestressing wire breakage increases, the prestress in the pipe decreases and the coating or concrete core begins to crack. Once the wire breakage becomes critical, the cylinder may burst and whole pipe may fail, depending on the internal pressure of the pipe. Therefore, actions must be taken at an early stage to avoid the final failure of the pipe and to make it function to the level of service. In current practice, steel liners are often used to strengthen the pipe. However, since the wire breakage activity will continue even after PCCP is repaired with steel liner, the effect of the on-going wire breakage on the structural integrity of the pipe lined needs to be analyzed. This paper presents structural analyses of PCCP reinforced with steel liner that suffers gradual wire breaks. In this paper, three different cases of PCCP before and after the lining were simulated. First, the structural condition of the pipe before the lining was calculated. This will help utilities to understand the actual condition of the pipe and justify their actions taken to reinforce the pipe. Second, the structural condition of the pipe after the lining was analyzed to have a better understanding regarding how much structural strength has been improved. Third, the performance of the lined pipe with new breakage of prestressing wires was investigated and the structural capacity of the pipe was analyzed. This helps utilities to understand how confident they can tolerate the ongoing wire breakage activities.