Weber Basin Water Conservancy District Opts for Trenchless Construction Utilizing Fusible PVC&trade Pipe in North Salt Lake, Utah

Over 6,000 LF of Fusible PVC® pipe was installed using two different trenchless construction methods in early 2012, along Center Street in North Salt Lake, Utah. The general contractor was responsible for design and installation under a design-build-bid format

Weber Basin Water Conservancy District requested general contractors to provide a plan to rehabilitate 3,000 feet of 10-inch diameter asbestos cement pipe (AC) and 18-inch diameter reinforced concrete cylinder pipe (RCCP) in the same construction corridor. Nearby oil refineries were the major users of both lines. The 18-inch RCCP line was also used for irrigating a nearby park. Both of the pipelines were near the end of their useful lives due to age. The initial bid allowed for the consideration of conventional open trench, pipe bursting, sliplining, or a combination of installation methods. The ability to pipe burst the AC pipe and leave it in the ground, eliminating the need for special (and more costly) disposal requirements, was an important consideration.

The owner determined that the municipal AC line required upsizing to 12-inch diameter (from 10-inch) and that the industrial RCCP line could be downsized to 12-inch diameter. Contractors could use HDPE, ductile iron, or PVC pipe as long as the selected material provided a minimum ID of 11.3-inches and a minimum pressure class of 200 psi. Final contractor selection was based on the following language from the bid documents: "The overall proposal that provides the best value, in the sole determination of the District, shall be selected as the successful proposal." There were three bids received, from which the District selected Whitaker Construction of Brigham City.

Having worked with Fusible PVC® pipe on multiple projects over the past few years, Whitaker proposed pipe bursting the 10-inch AC with 12-inch Fusible PVC® pipe and sliplining 12-inch Fusible PVC® pipe inside the existing 18-inch industrial RCCP line. Whitaker also elected to have its personnel trained and qualified in PVC fusion by Underground Solutions.

Since both lines were in a single corridor, the same pits could be used for both the sliplining and the pipe bursting operations. A TT Technologies hydraulic burst winch was used to pull the pipe for both applications. As the original lines were installed before Interstate 15 was constructed above them, there were some challenges with the proximity of other utilities. As with many trenchless rehabilitation projects, unplanned issues arose and were addressed using the team's experience and standard problem solving techniques. Whitaker Construction successfully pressure tested the lines to 200 psi a few months after starting the project. Project Manager, Branson Yantes of Whitaker Construction, provided the following insight, "This was a difficult project in a tight corridor, with a strict deadline. The installation and testing of the Fusible PVC® pipe went flawlessly."

Pipeline Details and Project Summary
Project: Center Street 10-Inch Treated and 18-Inch Untreated Water Pipeline Rehabilitation; North Salt Lake, Utah
Owner: Weber Basin Water Conservancy District; Layton, Utah
General Contractor: Whitaker Construction; Brigham City, UT
Fusion Contractor: Whitaker Construction; Brigham City, UT
Pipeburst Length: 3,080 LF 12" DR18 Fusible PVC®
Slipline Length: 3,040 LF 12: DR18 Fusible PVC®

12" Fusible PVC® pipe with bursting head prior to bursting 10" AC pipe

Fusible PVC® layout with insertion pit

TT Technologies bursting equipment in pit

12" Fusible PVC® pipe prior to pull-in

12" Fusible PVC® pipe with bursting head near insertion pit