CASE STUDY

96-in. PCCP Circulation Water Piping Rehabilitation at Apache Generating Station

Three 20 ft sections of 96-in. prestressed concrete cylinder pipe flagged by electromagnetic inspection were lined with a fully structural carbon FRP system from QuakeWrap®, following AWWA C305.

PRODUCT: WET LAYUP CFRP
APPLICATION: PCCP LINING
INDUSTRY: POWER GENERATION

GET A PIPE REPAIR CONSULTATION ALL PROJECTS

Looking down a 96-in. PCCP at Apache Generating Station lined with overlapping rings of carbon FRP before the top coat

82 psi internal pressure, plus external soil load

PCCP diameter: 96 in.
sections lined: 3 x 20 ft
internal pressure: 82 psi
installation: < 2 weeks

Project Details

OWNER: Arizona G&T Cooperatives, Inc., Apache Generating Station
LOCATION: Cochise, Arizona
STRUCTURE: 96-in. prestressed concrete cylinder pipe (PCCP) circulation water piping, three 20 ft sections
STANDARD: AWWA C305
LOADS: External soil pressure and 82 psi internal (hydrostatic) pressure
QUAKEWRAP® SYSTEM: Fully structural carbon FRP liner, internal wet layup (QW U27C and B41C carbon, QW B2610G glass at the end terminations)
FRP SYSTEM AND MATERIALS: QuakeWrap, Inc.
FRP INSTALLER: FRP Construction

01 · THE CHALLENGE

Three PCCP Segments in Immediate Need of Repair

Arizona G&T inspected the large-diameter PCCP circulation water piping at its Apache Generating Station with electromagnetic technology. Three segments were identified as in immediate need of structural repair.

The owner wanted the repair done with as little downtime as possible.

02 · THE SOLUTION

A Fully Structural Carbon FRP Liner to AWWA C305

QuakeWrap® recommended a fully structural carbon FRP liner for three 20 ft sections of the 96-in. pipe, provided specifications and design support, and supplied the materials. Following AWWA C305, the system can carry external soil pressure and 82 psi of internal hydrostatic pressure.

FRP Construction installed the liner by wet layup: a high-adhesion epoxy tack coat, seven layers of carbon fabric with extra tack coat along the seams, and a 20 mil epoxy top coat.

Epoxy top coat20 mil
Carbon FRP (QW U27C and B41C)7 layers
Epoxy tack coatHigh-adhesion bond
96-in. PCCPHost pipe

Carbon FRP layers going on inside the 96-in. PCCP with extra tack coat along the seams

03 · THE RESULT

Lined and Sealed in Less Than Two Weeks

At each end of the liner, QuakeWrap® dual glass fabric (B2610G) and an EPDM compression seal were placed over the glass and carbon layers, following the AWWA C305 end termination detail.

FRP Construction completed the installation successfully in less than two weeks, meeting the owner's goal of minimal downtime.