Post Installation Cracking of Reinforced Concrete Pipes - The Buried Facts

To best understand and evaluate cracking of Steel Reinforced Concrete Pipes (SRCP), engineers should review how SRCP is designed as a structural element, how serviceability and ultimate capacities are measured, and the interaction of pipe and bedding necessary to accommodate external loads.

This paper will review the basis of pipe structural and installation design, installation methods and practices, and the type and sources of load on SRCP. Crack orientation is another important factor that evaluators need to understand; the paper will detail types and possible causes of each crack type.

The paper will review the basic principles of pipe design, the requirements of current AS/NZS standards, and the recommendations of the pipe industry body, CPAA, and will present an evaluation tables and discussions that could be used as a guideline to evaluate the possible effect of cracks on structural integrity and durability of the pipeline and to advise when possible repairs or replacement are required. The paper will also review the most common SRCP cracking types in NZ and the possible causes and will highlight necessary actions for both designers and installers to avoid pipe cracking in future installations. An overview of some remedial actions used, there applicability, and possible outcomes will conclude the paper presentation.