Mechanical properties of prestressed concrete cylinder pipe with broken wires using distributed fiber optic sensors

Wire breakage is a major factor that results in the failure of prestressed concrete cylinder pipes (PCCPs). In this study, a prototype test was conducted on a PCCP specimen to evaluate its mechanical properties and possible failure modes with broken wires. The concrete core, steel cylinder, prestressing wires, and mortar coating of the PCCP were installed with specific distributed fiber optic sensors to measure the strain response. Additionally, a three-dimensional finite element model of PCCP was established, and the strain responses of PCCP with broken wires in different regions were assessed. The results demonstrated that the mortar coating gradually cracked with an increase in the wire breakage ratio, leading to mortar delamination and relaxation of prestressing wires, severely affecting the performance of the PCCP. Furthermore, cracking and spalling of the inner and outer concrete cores were observed, followed by yielding and leakage of the steel cylinder. The maximum wire breakage ratio of the PCCP specimen was 19.8% under the design internal pressure, and the minimum value of the measured influence range of wire breakage was approximately 140° at the central angle. The influence range of wire breakage gradually increased with an increase in the number of broken wires.