Joseph City, AZ

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.

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 Summary



Completion Date
Repair & Rehabilitation
Structures | Advanced Analysis | Applied Science & Research
Energy | Infrastructure & Transportation
Arizona Public Service Company
Specialized Capabilities
Repair & Strengthening | Buried Infrastructure | Materials Science

Key team members

Murat Engindeniz
Murat Engindeniz
Mehdi Zarghamee
Mehdi Zarghamee
Senior Principal