Use of CFRP as an External Repair for Structurally Deficient Pipes

摘要

Carbon fiber reinforced polymer (CFRP) can be an appropriate alternative to various methods of pipe replacement and repair for structurally deficient pipelines. When traditional pipe replacement, cured-in-place pipe and other types of repair are impractical, external CFRP can be used to reestablish the structural integrity of the pipeline. This paper will focus on four separate case studies where external wrapping using CFRP was used to provide added strength to structurally deficient pipelines. Nickajack Creek Watershed - The Nickajack Creek project consisted of a 24-inch pipe running across the Nickajack Creek in Mapleton, Georgia. The length between supports over the creek (roughly 45 feet) and access issues rendered traditional rehabilitation techniques impractical. CFRP was, therefore, selected to restore the structural integrity of the pipe with no disruption in service. ' City of Nashville - This project involved a 66-ft. section of 60-inch pre-stressed concrete cylindrical pipe (PCCP) that had a working pressure of 150 psi. After wire break analysis was conducted on the pipeline, structural repair was required on four separate areas of the pipeline. Due to the importance of the pipeline, it could not be taken out of service long enough to accommodate traditional repair techniques. Therefore, a specialized repair method was designed with the pipe being excavated, supported, and repaired while still full of water. Accotink Creek - Significant wire breaks on 30-inch and 42-inch PCCP force mains near the Accotink Creek required external CFRP repair. It was determined that external CFRP repair was the most appropriate solution due to internal diameters and the requirement for the pipe to remain in service during repair. City of Portland - The City of Portland project required a specialized repair due to the uniquely deteriorated condition of a 30-inch CCP pipeline running 270 feet underneath a pedestrian bridge. CFRP was installed on the outside while the pipe was still in service, providing additional strength to the host pipe.