As part of the City of Phoenix’s extensive Transmission Main Inspection and Assessment Program, a 1.2 mile reach of 48-inch Prestressed Concrete Cylinder Pipe (PCCP) was evaluated and determined to require rehabilitation. Although the selected and approved relining method was not unique, the diameter of the collapsed steel liner was the smallest diameter attempted. The unlined collapsed liner measured approximately 38-inches with a forming tolerance of +¼-” and -1″. The liner lapped nearly 26-½ inches, and expanded to 45-¾ inches within the 48″ PCCP host pipe. Prior to the selection and award of the collapsed steel liner, the fabricator formed, fabricated and tested a prototype for the City of Phoenix Water Department. The standard Non-Destructive Testing (NDT) procedures, and ultimately a proof-of-design hydrostatic test procedure were performed. The ends of the 3-piece segmental liner was capped on both ends, incrementally pressurized and held to a final test pressure of 250 psi.
The contract’s schedule as dictated by the COP was a challenge for all parties involved. From the time the contract was awarded and the Notice to Proceed was released, the construction schedule was shortened. Between the submittals, their respective approvals, receipt of materials and the start of fabrication, the fabricator’s schedule started at a 24/7 pace for the first 2-months of production. Another benefit was that the manufacturer’s proximity to the jobsite allowed for last minute changes to the CMAR’s planned delivery schedules.
The summary table may offer one an understanding of the level of complexity and challenge to weld all the elements or components. And to that, 420 completed liners of varying lengths and joint types. The plan and profile may best illustrate why a collapsed liner was the best option. The line, grade and the matching of the liner joints to those of the existing PCCP joints was a testament of the engineering, fabrication and contractor’s experience and the talent required to complete the project on time and within budget.
COLLAPSIBLE REHABILITATION LINER FOR 48″ PRESTRESSED CONCRETE CYLINDER PIPE (PCCP)
ELEMENTS
QTY. UNIT DESCRIPTION
6,252 LF 45″ COLLAPSIBLE LINER
726 EA 45″ ID Plate Rolled Liner Segments
421 EA Banded Bell Ends
16 EA Expansion Joint Banded Bells Ends
426 EA Bell Backer Plates
426 EA Longitudinal Seam Backer Plates
1,363 EA 2″ Dia. Grout Ports & Plugs
5,820 EA 1″ x 2″ Spacer Blocks
47 EA Beveled Ends
1,278 EA Tie Bars/Straps
40 EA Grout Rings
3 EA 24″ Field Welded Outlet Sleeves
8 EA 8″ Field Welded Outlet Sleeves
1 EA 6″ Field Welded Outlet Sleeves
4 EA 4″ Weld Lead Access Outlets
ACCESS PITS / PORTS – OPEN CUT
382 LF 48″/45″ DIAMETER WELDED STEEL PIPE CML X CMC
123 LF 48″ WELDED STEEL PIPE CML X CMC
259 LF 45″ WELDED STEEL PIPE CML X CMC
4 EA 4″ THREADED OUTLET COUPLING
1 EA 8″ FLANGE END COLLAR REINFORCED RADIAL OUTLETS
1 EA 12″ FLANGE END COLLAR REINFORCED RADIAL OUTLETS
5 EA 30″ FLANGE END COLLAR REINFORCED RADIAL OUTLETS
6 EA 6″ FLANGE END COLLAR REINFORCED TANGENT OUTLETS
11 EA 48″ FLANGE END ADAPTERS
8 EA 48″ X 44″ CONCENTRIC REDUCERS
12 EA 44″ BUTT STRAPS
8 EA 48″ BUTT STRAPS
2 EA 45″ BEVELS
2 EA 45″ 2-CUT ELBOWS
1 EA 45″ 3-CUT ELBOWS
1 EA 48″ CROTCH PLATE
Award Name
Pipe Fabrication
Company Name
Professional Piping Systems LLC
Award Year
2022
Product Details
- Scenario 3B Phase 2 & 3
- City of Phoenix Water Dept.
- Phoenix, AZ
Date Completed
January 1, 2022
Construction Standard
AWWA C608
Diameter
45"
Steel Tonnage Used
625
Steel Thickness
0.375"
Steel Fitting Type
Liners, Elbows, Outlets, Tees