Cholla Power Plant
Cholla Power Plant
Cholla Power Plant

Arizona Public Service Company (APS) chose SGH to perform a condition assessment and develop repairs for the circulating water pipelines at the Cholla Power Plant. The coal-fired power plant, co-owned and operated by APS, has four units, three of which include 66 in. and 72 in. diameter prestressed concrete cylinder pipe (PCCP) in their circulating water pipelines. The pipelines have been in service for thirty to fifty years and exhibited a high level of distress due to breaks in prestressing wires.

Scope | Solutions

Since 2008, SGH has helped APS minimize the risk of pipe failure and avoid unscheduled downtime by conducting condition assessments of the circulating water pipeline during both scheduled and emergency outages. Over the years, SGH has:

  • Performed internal visual and sounding inspections
  • Reviewed and verified electromagnetic inspection results by external wire continuity testing
  • Tested soil and mortar coating samples in the SGH laboratory
  • Performed failure risk analysis, and identified and prioritized pipes with a high risk of failure
  • Designed repairs using internally bonded CFRP liners and external post-tensioning
  • Provided bid support and assisted APS in selection of repair materials and contractors
  • Provided full-time engineering field support throughout repairs and verified compliance with project drawings and specifications
  • Assessed the quality of CFRP installations by performing bond tests on construction mock-ups and laboratory tension tests on sample panels
  • Provided recommendations for future inspections and maintenance

Project Contact(s)