Carbon FRP Strengthening of PCCP Aqueducts


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Title: Carbon FRP Strengthening of PCCP Aqueducts

Author(s): T. Alkhrdaji and J. Thomas

Publication: Special Publication

Volume: 215


Appears on pages(s): 349-360

Keywords: carbon fibers; load testing; prestressed concrete cylindrical pipes (PCCP); upgrading; water main; waterstop

Date: 8/1/2003

To prevent future blowouts of sections of the 50-year-old pipe, the Providence Water Supply Board decided to evaluate the condition of a main water pipeline. Non-destructive testing (NDT) investigations revealed that certain sections of the pipe were potentially deficient due to corrosion and breakage of the prestressing system. Strengthening of deficient sections was necessary to maintain the pipeline operational. A carbon fiber in-situ lining appeared to be the fastest, least disruptive, and most cost-effective upgrade solution. The specialty concrete repair contractor conducted full-scale tests to validate optimum FRP repair and waterstop termination design. In these tests, after the carbon fiber liner was installed, the prestressing strands of the FRPstrengthened section were cut leaving the FRP to be the only reinforcement. The test pipe was progressively pressurized until failure occurred at approximately 2-1/2 times the pipe service and surge pressures. The full-scale test proved the integrity of the system beyond theoretical prediction and assured the owner that strength was added to the pipe sections. The lightweight, flexible carbon fiber material along with thorough planning helped overcome challenging working conditions and provided a fast and effective upgrade solution.