Effect of the number of broken wire wraps on the structural performance of PCCP with full interaction at the gasket joint

Abstract

Broken prestressing wire wraps are the main cause of failure in prestressed concrete cylinder pipes (PCCP). The effect of the number and location of broken wire wraps on the structural performance of PCCP is investigated using advanced numerical modeling that considers full interaction between the spigot and bell ends of adjacent pipes. The stresses and strains in the various components of PCCP are evaluated with increasing internal pressure. A sensitivity analysis is performed to understand how manipulating the severity of the damage through varying the number of broken wire wraps affects the internal fluid pressure that causes failure. A 244-cm (96-in.) embedded cylinder pipe (ECP) is modeled with 5, 35, 70, and 100 broken wire wraps. The results obtained show that the internal fluid pressure required to cause failure can be as much as 14% lower when the damage is at the joint, and that the internal pressure that causes yielding of the wire wraps decreases approximately 65% as the severity of the damage increases from 5 to 100 broken wires.