Failure analysis of a prestressed concrete cylinder pipe under clustered broken wires by FEM

Abstract

The breakage of prestressed steel wires is the main cause of failure in prestressed concrete cylinder pipes (PCCPs). Current finite element models with clustered broken wires (CBW), which either remove all of the broken wire coils or consider the partial loss of prestress through simplified contact interactions, cannot reflect experimental phenomena such as the olive shape formed by wire breakpoints and the distribution of cracks in the concrete core. In this study, spring elements are inserted into the model through Python scripts to transfer the compressive prestress and simulate the breakage and bond-slip of steel wires. Moreover, a cohesive contact interaction is defined to simulate the delamination of the mortar coating. The results show that in the pipe subjected to a water pressure of 1.2 MPa, the number of CBW corresponding to the onset of visible cracks in the mortar, outer core, and inner core, yielding of the cylinder, and pipe failure are 20 (4.17%), 50 (10.42%), 70 (14.58%), 80 (16.67%), and 110 (22.92%), respectively. The number of CBW associated with pipe failure calculated by the proposed model falls between those of the other two current types of models.