Fifteen Years of Lessons Learned: Design and Construction of CFRP Liners for Large Diameter Pipelines

Strengthening of pressure pipelines using carbon fiber reinforced polymer (CFRP) materials has been an accepted repair method since the late 1990’s. CFRP composites are high strength, non-corrosive and durable materials and can add considerable structural capacity which makes them very suitable for pressure pipeline strengthening. However, there are several keys to success and best practices with regard to material selection, design, construction and quality control. There are lessons learned through installations which have taken place over the past fifteen years. These include adoption of criteria for material selection, new design philosophies, termination end detailing and critical points during the construction process. This paper provides state of the art information regarding materials, design considerations, installer experiences and current best practices. Field case studies provide a comprehensive review of the use of CFRP composites. 1. BACKGROUND Over the past fifteen years inspection methods for large diameter pipelines have evolved to include more accurate methods, failure risk analysis and repair prioritization. These advancements have provided utility owners with critical information regarding the exact location of distressed pipes and caused an increase in demand for targeted rehabilitation technologies. Based on this repair prioritization information, utilities have taken proactive steps in advance of failure to replace or repair the distressed pipes with an unacceptably high risk of failure. There are several repair options for concrete pressure pipes which include encasing the degraded pipe