Role of surge and possible mitigation in PCCP design

In a number of prestressed concrete cylinder pipe(PCCP) failures, the unfortunate events seem to have been precipitated by over-stressing of the pipeline due to surge events such as power failure, pump trip, and either closure or opening of the gates in the line faster than permissible. Historical accumulation of stresses due to one or more of these above operational problems also trigger the failure. In many cases, design engineers simply failed to do any form of surge calculations and failed to provide adequate surge protection measures as part of the overall design of the project. This paper provides a concise summary of sources of surge events, surge evaluation techniques, and surge mitigation measures for typical situations. Sizing and locating surge mitigation devices as well as the causes of secondary surge are also discussed in this paper.