Scattered Broken Wire Wrap Effects on Structural Capacity of Prestressed Concrete Cylinder Pipes

Broken prestressing wire wraps are the primary cause of failure in prestressed concrete cylinder pipes (PCCP). This work examines the potential effects of the distribution of broken and intact prestressing wire wraps on the overall strength of PCCP. An advanced computational model based on non-linear finite element analysis was used to model the effect of scattered broken wire wraps versus contiguous broken wire wraps on the structural performance of PCCP. This study considers two distributions for broken wire wraps: scattered broken wire wraps through the length of the pipe and contiguous broken wire wraps in the barrel of the pipe. A sensitivity analysis was performed to evaluate visible cracking of the concrete core, yielding of the prestressing wires, steel cylinder with increasing internal pressure, and increasing number of broken wire wraps. A 60” embedded cylinder pipe (ECP) is modeled with 30 broken wire wraps in ten (10) different scenarios. The results of the scattered and contiguous broken wire wraps were compared. This information can be used by water and wastewater utilities to better understand the strength of PCCP in cases where broken wire wraps are scattered through the length of the pipe, leading to better risk management, and failure prevention of PCCP.