Bringing Carbon Fiber Lining Design and Practices to the Next Level

Since Prestressed Concrete Cylinder Pipes (PCCP) were first introduced more than thirty years ago the demand for the repair of PCCP has been growing in numbers and diversity in recent times. The current repair methods available (additional post tensioning, steel lining, cured in place pipes, etc.) do not tackle effectively the case of external repair for large diameter pipes inaccessible from the outside. Relining by Carbon Fiber Reinforced Polymer (CFRP) is an appealing solution to this issue, not only because it is an internal repair method, thus not requiring excavation, but also because it adapts to a large range of pipe diameters, and can be expedited with the assistance of automated equipment. The aim of this paper is to outline the considerations involved with both the external post tensioning repair method and the CFRP repair method. Comparative advantages and disadvantages will be discussed. Finally, an automated method for performing CFRP repair will be introduced that may expand the application of CFRP repairs beyond spot, localized repairs and provide additional qualitative improvements to the application process. Concluding paragraphs will explain that the rehabilitation and repair process is a combined effort between owner, designer, and contractor/installer.