Destructive Testing of Steel Relined Prestressed Concrete Cylinder Pipe

The San Diego County Water Authority has a long history with rehabilitating prestressed concrete cylinder pipelines (PCCP) with steel liner plates, known as steel relining. In 1982, the Water Authority developed this method to rehabilitate long reaches of PCCP. Since then, the Water Authority has steel relined over 45-miles of PCCP assets and has established the technique as an efficient rehabilitation approach. To better understand the long-term performance of steel relined PCCP, Water Authority staff destructively tested two sections of steel relined PCCP in January 2018. The tested pipe was rehabilitated in 1985 using some of the very first design and construction methods for this technique. This paper will detail the removal, load testing procedure, the PCCP failure mode, the steel reline performance under loading, and document all the associated data. Since the relined pipe was designed for internal pressures only, the team focused on testing the capabilities for external loading. Overall the testing demonstrated the steel liners are very robust for external loading. After the PCCP failed, the relined steel is very strong and behaves like a composite pipe with the PCCP cylinder and inner core.