Snap, Crack, Pop — Recording of a Prestressed Pipe Failure

The San Diego County Water Authority has over 400 kilometers of large diameter pipelines that provides up to 95 percent of the water to San Diego County's 3 million people. Of the 400 km of pipelines, 133 km is made of prestressed concrete cylinder pipe (PCCP) manufactured between 1958 and 1982, and 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 Water Authority implemented the Aqueduct Protection Program (APP) in 1992 which includes the condition assessment of the Water 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 March 2006, the Water Authority installed 17.1 km of acoustic fiber optic (AFO) cable to monitor wire break activity and to provide critical information on the remaining service life of the pipeline. During the commissioning of the AFO system, there was a catastrophic failure on a section of the pipeline. This paper discusses the equipment, results and accuracy of the AFO system.