Do Broken Prestressing Wire Wraps at the Joint Affect the Safe Operation of a Pipe?

Abstract

Broken prestressing wire wraps are the main cause of failure in prestressed concrete cylinder pipe (PCCP) and are typically caused by corrosion, hydrogen embrittlement, overloading, high internal pressures, and manufacturing defects. In a previous study, it was shown that without considering the interaction between two (2) adjacent pipes, broken wire wraps at the joint reduce the strength of a PCCP. In this study, the effect of broken wire wraps on the structural integrity of a damaged PCCP was investigated considering full interaction and perfect bond between the spigot and bell ends of adjacent pipes. The stress and strain in the various components of a damaged PCCP were investigated by increasing the internal pressure of the pipe while varying the number of broken prestressing wire wraps (i.e., manipulating the severity of the damage). The results were calculated for a 96-inch embedded cylinder pipe (ECP) design with 5, 35, 70, and 100 broken wire wraps. Based upon the results obtained, a comparison between the effect of the broken wire wraps in the barrel of the pipe and broken wire wraps at the joint is presented and discussed.