Coming Down the Pipeline: Asset Management of PCCP Conveyance Systems

A condition assessment was initiated for the Bay Division Pipeline 4 (BDPL4) with the goal of improving reliability of the pipeline and extending useful service life in a cost effective manner. Electromagnetic and internal sounding inspections were the primary approaches used to evaluate the prestressed concrete cylinder pipe (PCCP) condition. A structural risk analysis identified and prioritized critical pipe segments in need of additional investigation measures or immediate repair. A seismic risk analysis was performed to detect lengths of the pipeline that are susceptible to joint pullout due to ground shaking, and liquefaction and landslide failure following an earthquake. A present value worth analysis found that extending the life expectancy of the BDPL4 was the most cost effective approach to execute into the asset management plan. As a result, contemporary PCCP rehabilitation and monitoring methods were researched and post tensioning of the critical PCCP segments via tendon straps was selected as the preferred repair method and electromagnetic and internal sounding inspection procedures will continue while also introducing acoustic monitoring for monitoring. A Geographic Information Systems (GIS) geo-database provides the means to track changes to the pipeline over time to support a long-term asset management program over the remaining lifetime of the PCCP.