Detecting Damaged Prestressed Concrete Cylinder Pipe Using Remote Field Eddy Current/Transformer Coupling Technology

The San Diego County Water Authority (Authority) has over 400 kilometers (km) of large diameter pipelines that provides up to 95 percent of the water to San Diego County's 2.7 million people. In this 400 km is 133 km of prestressed concrete cylinder pipe (PCCP) manufactured between 1958 and 1982 ranging in diameters of 168 cm to 244 cm. In order to provide a safe and reliable supply of water to San Diego County, the Authority implemented the Aqueduct Protection Program (APP) in 1992 which includes the condition assessment of the Authority's PCCP. Part of the program consists of developing and researching new non-invasive/non-destructive inspection procedures to determine the condition of existing PCCP. In June 1999, the Authority experimented with Remote Field Eddy Current/Transformer Coupling (RFEC/TC) measurements on 5 km of 175 cm PCCP installed in 1959. This paper discusses the equipment, investigative procedures, results and accuracy of RFEC/TC.