Full-scale experiment and numerical simulation of prestressed concrete cylinder pipe with broken wires strengthened by prestressed CFRP

Prestressed concrete cylinder pipe (PCCP) is widely used in large-scale water supply projects. The most common damage mode of PCCP is caused by rupture of prestressed wires. To strengthen a damaged PCCP, the technology of wrapping prestressed carbon fiber reinforced polymer (CFRP) externally is proposed. A full-scale test on a PCCP with an inside diameter of 1400 mm and a length of 6000 mm is conducted. In the test, three pipe sections are selected with broken wires, unbroken wires, and broken wires but repaired by prestressed CFRP. The strain response of the material in each section is analyzed by applying stepwise increased internal water pressure. Then, a finite element model is established and calibrated. Compared with the section containing broken wires, the material strain of the section repaired by prestressed CFRP decreases with almost no damage, indicating that prestressed CFRP is an effective repair method for damaged PCCP. Additionally, the influence area of broken wires is rather limited, showing negligible effect beyond a distance of 1300 mm from the broken wire area. When a PCCP reaches the serviceability limit state, prestressed CFRP repair and non-prestressed CFRP repair can increase the bearing capacity of the pipe by 87.3% and 34.9%, respectively.

Automated summary

Prestressed CFRP repair is an effective method to repair damaged PCCP, significantly reducing material strain with almost no damage. The influence area of broken wires is limited, and both non-prestressed CFRP repair and prestressed CFRP repair can increase the pipe's bearing capacity.