Val Vista Transmission Main rehabilitation

Project Owner: City of Phoenix
Project Type: Construction Manager at Risk
Construction Dates: GMP 1: 10/17 to 02/18 and GMP 2: 11/18 to 01/19

The award-winning Val Vista Transmission Main Rehabilitation CMAR project included the rehabilitation of more than 8,000 lineal feet of 90-inch to 96-inch transmission main using a welded steel liner. The pipeline was accessed via six different portal (pit) locations in the City of Mesa and advanced shoring and confined space procedures ensured safety at all times. The scope of work was split into two GMPs and completed during two planned shutdowns of the Val Vista Transmission Main. This was the shortest duration for a rehabilitation project of this size that has ever been completed for the City of Phoenix. The team worked together to rehabilitate a critical transmission main within two strict deadlines and delivered the project on time, within budget, and with minimal impacts to area stakeholders.

GMP 1 included the rehabilitation of 3,109 LF of 96" transmission main. GMP 2 included the rehabilitation of 4,901 LF of 90" to 96" transmission main. The scope of work for rehabilitation included the following:

  • Dewatering of the existing transmission main.

  • Excavation and backfill of access portals.

  • Demolition and removal of the existing PCCP transmission main at access portals.

  • Installation of new welded steel liner inside the existing PCCP transmission main.

  • Grout annular space between the inside of the existing transmission main and the outside of the newly installed welded steel liner.

  • Cement mortar lining the interior of the newly installed welded steel liner.

  • Installation of closure piping at the access portal locations.

  • Fill, flush, test, and disinfect the previously dewatered section of transmission main.